EP2804450B1 - Insulating member for a plasma arc torch consisting of several parts, torch and related assemblies equipped with the same and associated method - Google Patents

Description

The present invention relates to a multi-part insulating part for an arc plasma torch, in particular a plasma cutting torch, for electrical insulation between at least two electrically conductive components of the plasma torch, arrangements and plasma torches with such an insulating part, plasma torch with such an arrangement and methods for processing a workpiece with a thermal plasma , plasma cutting and plasma welding.

Plasma torches are generally used for the thermal processing of electrically conductive materials such as steel and non-ferrous metals. Plasma welding torches are used for welding and plasma cutting torches for cutting electrically conductive materials such as steel and non-ferrous metals. Plasma torches usually consist of a torch body, an electrode, a nozzle and a holder for it. Modern plasma torches also have a nozzle protection cap fitted over the nozzle. A nozzle is often fixed using a nozzle cap.

Depending on the type of plasma torch, the components that wear out during operation of the plasma torch as a result of the high thermal load caused by the arc are, in particular, the electrode, the nozzle, the nozzle cap, the nozzle protective cap, the tip guard bracket and the plasma gas guide and shield gas guide parts. These components can be easily changed by an operator and are therefore referred to as wearing parts.

The plasma torches are connected by leads to a power source and a gas supply which feed the plasma torch. Furthermore, the plasma torch can be connected to a cooling device for a cooling medium, such as a cooling liquid.

Particularly high thermal loads occur with plasma cutting torches. This is due to the strong constriction of the plasma jet by the nozzle bore. Here, compared to plasma welding, small holes are used in relation to the cutting current, thus high current densities of 50 to 150 A/mm ² in the nozzle hole, high energy densities of approx. 2×10 ⁶ W/cm ² and high temperatures of up to 30,000 K be generated. Furthermore, higher gas pressures, usually up to 12 bar, are used in plasma cutting torches. The combination of high temperature and high kinetic energy of the plasma gas flowing through the nozzle bore causes the workpiece to melt and the melt to be expelled. A kerf is created and the workpiece is separated. In plasma cutting, oxidizing gases are often used to cut unalloyed steel. This also leads to a high thermal load on the wearing parts and the plasma cutting torch.

The plasma cutting torches are discussed in detail below.

A plasma gas flows between the electrode and the nozzle. The plasma gas is guided through a gas guide part, which can also be made up of several parts. This allows the plasma gas to be directed in a targeted manner. It is often rotated around the electrode by a radial and/or axial offset of the openings in the plasma gas guide part. The plasma gas guide part is made of electrically insulating material, since the electrode and the nozzle must be electrically isolated from each other. This is necessary because the electrode and nozzle have different electrical potentials during operation of the plasma cutting torch. To operate the plasma cutting torch, an arc is generated between the electrode and the nozzle and/or the workpiece, which ionizes the plasma gas. To ignite the arc, a high voltage can be applied between the electrode and the nozzle, which provides for a pre-ionization of the distance between the electrode and the nozzle and thus for the formation of an arc. The arc burning between the electrode and the nozzle is also known as the pilot arc.

The pilot arc exits through the nozzle bore and strikes the workpiece, ionizing the path to the workpiece. This allows the arc to form between the electrode and the workpiece. This arc is also referred to as the main arc. The pilot arc can be switched off during the main arc. However, it can also continue to be operated. During plasma cutting, this is often switched off in order not to put additional strain on the nozzle.

In particular, the electrode and the nozzle are thermally highly stressed and must be cooled. At the same time, they must also conduct the electrical current that is required to form the arc. For this reason, materials that conduct heat well and materials that conduct electricity well, usually metals such as copper, silver, aluminum, tin, zinc, iron or alloys containing at least one of these metals, are used for this purpose.

The electrode often consists of an electrode holder and an emissive insert made of a material that has a high melting temperature (>2000°C) and a lower electron work function than the electrode holder. The materials used for the emission insert are non-oxidizing plasma gases such as argon, hydrogen, nitrogen, helium and mixtures thereof, tungsten when using, and nitrogen-oxygen mixture and mixtures when using oxidizing gases such as oxygen, air and mixtures thereof used with other gases, hafnium or zirconium.

The high-temperature material can be fitted into an electrode holder, which consists of a material that conducts heat and electricity well, for example by being pressed in with a form fit and/or force fit.

The electrode and nozzle can be cooled by gas, for example the plasma gas or a secondary gas, which flows along the outside of the nozzle. However, cooling with a liquid, such as water, is more effective. The electrode and/or the nozzle are often cooled directly with the liquid, i.e. the liquid is in direct contact with the electrode and/or the nozzle. In order to guide the cooling liquid around the nozzle, there is a nozzle cap around the nozzle, the inner surface of which together with the outer surface of the nozzle forms a coolant space in which the coolant flows.

In modern plasma cutting torches there is also a nozzle protection cap outside the nozzle and/or the nozzle cap. The inner surface of the nozzle guard and the outer surface of the nozzle or nozzle cap form a space through which a shield or shield gas flows. The secondary or protective gas emerges from the hole in the nozzle protection cap and envelops the plasma jet and ensures a defined atmosphere around it. In addition, the shielding gas protects the tip and tip guard from arcing that can form between the tip and the workpiece. These are called double arcs and can damage the nozzle. Especially when piercing the workpiece, the nozzle and the nozzle protection cap are heavily loaded by hot material spraying up. The secondary gas, the volume flow of which can be higher when piercing compared to the value when cutting, keeps the spraying material away from the nozzle and the nozzle protection cap and thus protects against damage.

The nozzle protection cap is also subjected to high thermal loads and must be cooled. For this reason, materials that conduct heat well and materials that conduct electricity well, usually metals such as copper, silver, aluminum, tin, zinc, iron or alloys containing at least one of these metals, are used for this purpose.

However, the electrode and the nozzle can also be cooled indirectly. They are connected to a component made of a material that conducts heat and electricity well, usually a metal such as copper, silver, aluminum, tin, zinc, iron or alloys containing at least one of these metals , contacted by touch. This component is in turn cooled directly, i.e. it is in direct contact with the mostly flowing coolant. At the same time, these components can serve as holders or receptacles for the electrode, the nozzle, the nozzle cap or the nozzle protection cap, and can conduct the heat away and supply the current.

There is also the possibility that only the electrode or only the nozzle is cooled with liquid. It is precisely in this case that the temperatures on the only gas-cooled component are often too high, which then wears out quickly or is even destroyed. This also leads to large temperature differences between the components in the plasma cutting torch and thus to mechanical stresses and additional stresses.

The nozzle protection cap is usually only cooled by the secondary gas. Arrangements are also known in which the nozzle protection cap is cooled directly or indirectly by a cooling liquid.

Gas cooling (plasma gas and/or secondary gas cooling) has the disadvantage that it is not effective and the required gas volume flow is very high in order to achieve acceptable cooling or heat dissipation. Plasma cutting torches with water cooling, for example, require gas flow rates of 500 l/h to 4000 l/h, while plasma cutting torches without water cooling require gas flow rates of 5000 to 11000 l/h. These ranges depend on the cutting currents used, which can be in a range from 20 to 600 A, for example. At the same time, the volume flow of the plasma gas and/or secondary gas should be selected in such a way that the best cutting results are achieved. Volume flows that are too high, which are necessary for cooling, often worsen the cutting result.

In addition, the high gas consumption caused by large volume flows is uneconomical.

This applies in particular when gases other than air, e.g. argon, nitrogen, hydrogen, oxygen or helium, are used.

The use of direct water cooling for all wearing parts, on the other hand, is very effective, but leads to an increase in the dimensions of the plasma cutting torch, since, for example, the cooling channels are necessary to guide the cooling liquid to and from the wearing part to be cooled. In addition, great care is required when changing the directly liquid-cooled consumables, as no coolant should remain between the consumables in the plasma cutting torch, as this can damage the plasma torch when the arc is ignited.

The invention is therefore based on the object of providing more effective cooling of components, in particular wearing parts, of a plasma torch.

WO 94088748 A1 discloses an example of a one-piece insulator for a plasma arc torch.

US6169370B1 discloses an example of a two-piece insulator for a cold plasma torch.

According to a first aspect, this object is achieved by a multi-part insulating part according to claim 1.

The expression "electrically non-conductive" is also intended to include that the material of the plasma torch insulating part is slightly or not significantly electrically conductive. The insulating part can, for example, be a plasma gas routing part, secondary gas routing part or cooling gas routing part.

Furthermore, this object is achieved according to a second aspect by a multi-part insulating part according to claim 3.

According to a third aspect, this object is achieved by a multi-part insulating part according to claim 4.

According to a further aspect, this object is achieved by a method according to claim 22.

Embodiments of the invention are disclosed in the dependent claims.

Other examples disclosed in the specification are useful for understanding the invention.

The invention is based on the surprising finding that by using a material that not only does not conduct electricity but also conducts heat well, a more effective and cheaper cooling is possible and smaller and simpler designs of plasma torches are possible and lower temperature differences and thus lower mechanical stresses can be achieved.

At least in one or more particular embodiment(s), the invention provides a cooling of components, in particular wearing parts, of a plasma torch that is more effective and/or cheaper and/or leads to lower mechanical stresses and/or enables smaller and/or simpler plasma torch designs and at the same time to ensure the electrical insulation between components of a plasma torch.

• Figur 1 eine Seitenansicht teilweise im Längsschnitt von einem Plasmabrenner gemäß einer ersten besonderen Ausführungsform der Erfindung;
• Figur 2 eine Seitenansicht teilweise im Längsschnitt von einem Plasmabrenner gemäß einer zweiten besonderen Ausführungsform der Erfindung;
• Figur 3 eine Seitenansicht teilweise im Längsschnitt von einem Plasmabrenner gemäß einer dritten besonderen Ausführungsform der Erfindung;
• Figur 4 eine Seitenansicht teilweise im Längsschnitt von einem Plasmabrenner gemäß einer vierten besonderen Ausführungsform der Erfindung;
• Figur 5 eine Seitenansicht teilweise im Längsschnitt von einem Plasmabrenner gemäß einer fünften besonderen Ausführungsform der Erfindung;
• Figur 6 eine Seitenansicht teilweise im Längsschnitt von einem Plasmabrenner gemäß einer sechsten besonderen Ausführungsform der Erfindung;
• Figur 7 eine Seitenansicht teilweise im Längsschnitt von einem Plasmabrenner gemäß einer siebten besonderen Ausführungsform der Erfindung;
• Figur 8 eine Seitenansicht teilweise im Längsschnitt von einem Plasmabrenner gemäß einer achten besonderen Ausführungsform der Erfindung;
• Figur 9 eine Seitenansicht teilweise im Längsschnitt von einem Plasmabrenner gemäß einer neunten besonderen Ausführungsform der Erfindung;
• Figuren 10a und 10b eine Längsschnittansicht sowie eine teilweise geschnittene Seitenansicht von einem Isolierteil gemäß einer besonderen Ausführungsform der Erfindung;
• Figuren 11a und 11b eine Längsschnittansicht sowie eine teilweise geschnittene Seitenansicht von einem Isolierteil gemäß einer weiteren besonderen Ausführungsform der Erfindung;
• Figuren 12a und 12b eine Längsschnittansicht sowie eine teilweise geschnittene Seitenansicht von einem Isolierteil gemäß einer weiteren besonderen Ausführungsform der Erfindung;
• Figuren 13a und 13b eine Längsschnittansicht sowie eine teilweise geschnittene Seitenansicht von einem Isolierteil gemäß einer weiteren besonderen Ausführungsform der Erfindung;
• Figuren 14a und 14b eine Längsschnittansicht sowie eine teilweise geschnittene Seitenansicht von einem Isolierteil gemäß einer weiteren besonderen Ausführungsform der Erfindung;
• Figuren 14c und 14d Ansichten wie die Figuren 14a und 14b, wobei jedoch ein Teil weggelassen ist;
• Figuren 15a und 15b eine Draufsicht teilweise im Schnitt bzw. eine Seitenansicht teilweise im Schnitt von einem Isolierteil, das bspw. in dem Plasmabrenner der Figuren 6 bis 9 eingesetzt ist bzw. eingesetzt werden kann;
• Figuren 16a und 16b eine Draufsicht teilweise im Schnitt bzw. eine Seitenansicht teilweise im Schnitt von einem Isolierteil, das bspw. in dem Plasmabrenner der Figuren 6 bis 9 eingesetzt ist bzw. eingesetzt werden kann;
• Figuren 17a und 17b eine Draufsicht teilweise im Schnitt bzw. eine Seitenansicht teilweise im Schnitt von einem Isolierteil, das bspw. in dem Plasmabrenner der Figuren 6 bis 9 eingesetzt ist bzw. eingesetzt werden kann;
• Figuren 18a bis 18d eine Draufsicht teilweise im Schnitt sowie geschnittene Seitenansichten von einem Isolierteil gemäß einer weiteren besonderen Ausführungsform der vorliegenden Erfindung;
• Figuren 19a bis 19d Schnittansichten von einer Anordnung aus einer Düse und einem Isolierteil gemäß einer besonderen Ausführungsform der Erfindung;
• Figuren 20a bis 20d Schnittansichten von einer Anordnung aus einer Düsenkappe und einem Isolierteil gemäß einer besonderen Ausführungsform der vorliegenden Erfindung;
• Figuren 21a bis 21d Schnittansichten von einer Anordnung aus einer Düsenschutzkappe und einem Isolierteil gemäß einer besonderen Ausführungsform der vorliegenden Erfindung;
• Figuren 22a und 22b Teilschnittansichten einer Anordnung aus einer Elektrode und einem Isolierteil gemäß einer besonderen Ausführungsform der vorliegenden Erfindung; und
• Figur 23 eine Seitenansicht teilweise im Längsschnitt von einer Anordnung aus einer Elektrode und einem Isolierteil gemäß einer besonderen Ausführungsform der vorliegenden Erfindung.

Further features and advantages of the invention result from the appended claims and the following description, in which several exemplary embodiments are described with reference to the schematic drawings. Thereby shows/show:

• figure 1 a side view, partly in longitudinal section, of a plasma torch according to a first particular embodiment of the invention;
• figure 2 a side view, partly in longitudinal section, of a plasma torch according to a second particular embodiment of the invention;
• figure 3 a side view, partly in longitudinal section, of a plasma torch according to a third particular embodiment of the invention;
• figure 4 a side view, partly in longitudinal section, of a plasma torch according to a fourth particular embodiment of the invention;
• figure 5 a side view, partly in longitudinal section, of a plasma torch according to a fifth particular embodiment of the invention;
• figure 6 a side view, partially in longitudinal section, of a plasma torch according to a sixth particular embodiment of the invention;
• figure 7 12 is a side view, partially in longitudinal section, of a plasma torch according to a seventh particular embodiment of the invention;
• figure 8 a side view, partially in longitudinal section, of a plasma torch according to an eighth particular embodiment of the invention;
• figure 9 12 is a side view, partially in longitudinal section, of a plasma torch according to a ninth particular embodiment of the invention;
• Figures 10a and 10b a longitudinal sectional view and a partially sectional side view of an insulating part according to a particular embodiment of the invention;
• Figures 11a and 11b a longitudinal sectional view and a partially sectional side view of an insulating part according to a further particular embodiment of the invention;
• Figures 12a and 12b a longitudinal sectional view and a partially sectional side view of an insulating part according to a further particular embodiment of the invention;
• Figures 13a and 13b a longitudinal sectional view and a partially sectional side view of an insulating part according to a further particular embodiment of the invention;
• Figures 14a and 14b a longitudinal sectional view and a partially sectional side view of an insulating part according to a further particular embodiment of the invention;
• Figures 14c and 14d views like that Figures 14a and 14b , but with a part omitted;
• Figures 15a and 15b Fig. 12 is a partially sectional plan view and a partially sectional side view, respectively, of an insulating member used, for example, in the plasma torch of Figs Figures 6 to 9 is used or can be used;
• Figures 16a and 16b Fig. 12 is a partially sectional plan view and a partially sectional side view, respectively, of an insulating member used, for example, in the plasma torch of Figs Figures 6 to 9 is used or can be used;
• Figures 17a and 17b Fig. 12 is a partially sectional plan view and a partially sectional side view, respectively, of an insulating member used, for example, in the plasma torch of Figs Figures 6 to 9 is used or can be used;
• Figures 18a to 18d 12 is a partially sectioned plan view and side sectional views of an insulating member according to another particular embodiment of the present invention;
• Figures 19a to 19d Sectional views of an arrangement of a nozzle and an insulating part according to a particular embodiment of the invention;
• Figures 20a to 20d sectional views of a nozzle cap and insulating member assembly according to a particular embodiment of the present invention;
• Figures 21a to 21d sectional views of an assembly of a nozzle protection cap and an insulating part according to a particular embodiment of the present invention;
• Figures 22a and 22b Partial sectional views of an arrangement of an electrode and an insulating part according to a particular embodiment of the present invention; and
• figure 23 12 is a side view, partially in longitudinal section, of an electrode and insulating member assembly according to a particular embodiment of the present invention.

figure 1 Figure 12 shows a liquid-cooled plasma cutting torch 1 according to a particular embodiment of the present invention. It comprises an electrode 2, an insulating part designed as a plasma gas guiding part 3 for guiding plasma gas PG and a nozzle 4. The electrode 2 consists of an electrode holder 2.1 and an emission insert 2.2. The electrode holder 2.2 consists of a material that is a good conductor of electricity and heat, in this case a metal, for example copper, silver, aluminum or an alloy containing at least one of these metals. The emission insert 2.2 is made from a material that has a high melting point (>2000° C.). When using non-oxidizing plasma gases (e.g. argon, hydrogen, nitrogen, helium and mixtures thereof), e.g. tungsten is suitable here and when using oxidizing gases (e.g. oxygen, air, mixtures thereof, nitrogen-oxygen mixture) e.g. hafnium or Zirconium. The emission insert 2.2 is placed in the electrode holder 2.1. The electrode 2 is shown here as a flat electrode in which the emission insert 2.2 does not protrude beyond the surface of the front end of the electrode holder 2.1.

The electrode 2 protrudes into the hollow interior 4.2 of the nozzle 4. The nozzle is screwed with a thread 4.20 into a nozzle holder 6 with an internal thread 6.20. The plasma gas guide part 3 is arranged between the nozzle 4 and the electrode 2 . In which Plasma gas guide part 3 has bores, openings, grooves and/or recesses (not shown) through which the plasma gas PG flows. The plasma gas PG can be made to rotate by a corresponding arrangement, for example with a radial offset and/or an inclination to the center line M of radially arranged bores. It serves to stabilize the arc or the plasma jet.

The arc burns between the emission insert 2.2 and a workpiece (not shown) and is constricted by a nozzle hole 4.1. The arc itself already has a high temperature, which is increased by its constriction. Temperatures of up to 30,000 K are reported. Therefore, the electrode 2 and the nozzle 4 are cooled with 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 cooling medium. Liquid cooling is considered the most effective. In an interior space 2.10 of the electrode 2 there is a cooling tube 10 through which the coolant flows from the coolant supply line WV2 through the coolant space 10.10 to the electrode 2 in the vicinity of the emission insert 2.2 and through the space extending from the outer surface of the cooling tube 10 into the inner surface of the Electrode 2 is formed, is returned to the coolant return WR2.

In this example, the nozzle 4 is cooled indirectly via the nozzle holder 6, to which the coolant is conducted away again (WR1) through a coolant space 6.10 (WV1) and via a coolant space 6.11. The coolant usually flows at a volume flow of 1 to 10 l/min. The nozzle 4 and the nozzle holder 6 consist of a metal. Due to 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 holder 6, the heat generated in the nozzle 4 is conducted into the nozzle holder 6 and dissipated by the flowing cooling medium (WV1, WR1).

The insulating part designed as a plasma gas guide part 3 is designed in one piece in this example and consists of an electrically non-conductive material that is a good heat conductor. Electrical insulation between the electrode 2 and the nozzle 4 is achieved by using such an insulating part. This is necessary for the operation of the plasma cutting torch 1, namely the high-voltage ignition and the operation of a pilot arc burning between the electrode 2 and the nozzle 4. At the same time, heat is conducted between the electrode 2 and the nozzle 4 from the warmer to the colder component via the insulating part, which is designed as a plasma gas guide part 3 and is a good conductor of heat. So there is an additional heat exchange via the insulating part. The plasma gas guiding part 3 is in contact with the electrode 2 and the nozzle 4 by contact via contact surfaces.

In this embodiment, a contact surface 2.3 is, for example, a cylindrical outer surface of the electrode 2 and a contact surface 3.5 is a cylindrical inner surface of the plasma gas guiding part 3. A contact surface 3.6 is a cylindrical outer surface of the plasma gas guiding part 3 and a contact surface 4.3 is a cylindrical inner surface of the nozzle 4 a loose fit with little play, e.g. H7/h6 according to DIN EN ISO 286, between the cylindrical inner and outer surfaces is used in order on the one hand to plug into one another and on the other hand to achieve good contact and thus low thermal resistance and thus good heat transfer. The heat transfer can be improved by applying thermal paste to these contact surfaces. (Note: Even if a thermal compound is used, this should still fall under the term "direct contact".) Then a fit with a larger clearance, for example H7/g6, can be used. Furthermore, the nozzle 4 and the plasma gas guide part 3 each have a contact surface 4.5 and 3.7, which are annular surfaces here and are in contact with one another by touching. This is a non-positive connection between the annular surfaces, which is realized by screwing the nozzle 4 into the nozzle holder 6 .

Due to the good thermal conductivity, high temperature differences between the nozzle 4 and the electrode 2 can be avoided and mechanical stresses caused thereby in the plasma cutting torch 1 can be reduced.

A ceramic material is used here by way of example as an electrically non-conductive and heat-conductive material. Aluminum nitride, which according to DIN 60672 has very good thermal conductivity (approx. 180 W/(m ^∗ K) and high specific electrical resistance (approx. 10 ¹² Ω ^∗ cm), is particularly suitable.

In figure 2 a cylindrical plasma cutting torch 1 is shown in which the electrode 2 is directly cooled with coolant. The one in the figure 2 shown indirect cooling of the nozzle 4 via the nozzle holder 6 is not available. The nozzle 4 is cooled by heat conduction via an insulating part designed as a plasma gas guide part 3 to the electrode 2, which is directly cooled with coolant. By using such an insulating part, electrical insulation between the electrode 2 and the nozzle 4 is achieved. This is necessary for the operation of the plasma cutting torch 1, namely the high-voltage ignition and the operation of the pilot arc burning between the electrode 2 and the nozzle 4. At the same time, heat is conducted between the electrode 2 and the nozzle 4 from the warmer to the colder component via the insulating part, which is designed as a plasma gas guide part 3 and is a good conductor of heat. There is therefore an additional exchange of heat via the plasma gas guide part 3 between the electrode 2 and the nozzle 4. The plasma gas guide part 3 is in contact with the electrode and the nozzle 4 through contact via contact surfaces.

In this exemplary embodiment, a contact surface 2.3 is, for example, a cylindrical outer surface of the electrode 2 and a contact surface 3.5 is a cylindrical inner surface of the plasma gas guiding part 3. A contact surface 3.6 is a cylindrical outer surface of the plasma gas guiding part 3 and a contact surface 4.3 is a cylindrical inner surface of the nozzle 4. Preferably, here a loose fit with little clearance, for example H7/h6 according to DIN EN ISO 286, between the cylindrical inner and outer surfaces is used in order to on the one hand the nesting and on the other hand a good contact and thus low thermal resistance and thus good heat transfer. The heat transfer can be improved by applying thermal paste to these contact surfaces. Then a fit with more play, for example H7/g6, can be used. Furthermore, the nozzle 4 and the plasma gas guide part 3 each have a contact surface 4.5 or 3.7, which are annular surfaces here and are in contact with one another by touching. This is a non-positive connection between the annular surfaces, which is realized by screwing the nozzle 4 into the nozzle holder 6 .

The omission of the indirect cooling for the nozzle 4 leads to a considerable simplification of the structure of the plasma cutting torch 1, since the coolant spaces of the nozzle holder 6, which are otherwise necessary to carry the coolant back and forth, are omitted. The electrode is cooled as in figure 1 .

In the figure 3 a plasma cutting torch 1 is shown, in which a nozzle 4 is indirectly cooled via a nozzle holder 6, to which the coolant is guided through a coolant space 6.10 (WV1) and away again via a coolant space 6.11 (WR1). The in the figures 1 and 2 shown direct cooling of the electrode 2 is not provided. The conduction of heat from the electrode 2 to the nozzle 4 takes place via an insulating part designed as a plasma gas guide part 3 to the indirect coolant-cooled nozzle 4. In this regard, the statements relating to FIGS figures 1 and 2 .

This leads to a significant simplification of the structure of the plasma torch 1 and the electrode 2, since in the figures 1 and 2 Cooling pipe 10 shown and the coolant spaces 2.10 and 10.10 are omitted, which are otherwise necessary to carry the coolant back (WV2) and away again (WR2).

The Indian figure 4 shown plasma cutting torch 1 differs from that in FIG figure 1 plasma cutting torch shown is that the nozzle 4 is directly cooled with a coolant. For this purpose, the nozzle 4 is fixed by a nozzle cap 5 . An internal thread 5.20 of the nozzle cap 5 is screwed to an external thread 6.21 of a nozzle holder 6. The outer surface of the nozzle 4 and a part of the nozzle holder 6 as well as the inner surface of the nozzle cap 5 form a coolant space 4.10, through which the coolant, which flows through the coolant spaces 6.10 and 6.11 of the nozzle mount 6 (WV1) and back (WR1), flows.

Between the nozzle 4 and an electrode 2 there is an insulating part designed as a plasma gas guiding part 3 . This achieves the same advantages as in connection with the figure 1 are explained. The heat is transferred between the electrode 2 and the nozzle 4 from the warmer to the colder component via the insulating part, which is designed as a plasma gas guide part 3 and has good thermal conductivity. The plasma gas guiding part 3 is in contact with the electrode 2 and the nozzle 4 by contact. In this way, mechanical stresses in the plasma cutting torch 1 caused by high temperature differences can be reduced.

An advantage over the in 1 Plasma cutting torch shown is that the directly coolant-cooled nozzle 4 is better cooled than the indirectly cooled. Since the coolant flows in this arrangement up to the vicinity of the nozzle tip and a nozzle bore 4.1, where the greatest heating of the nozzle occurs, the cooling effect is particularly great. The coolant chamber is sealed by O-rings between the nozzle cap 5 and the nozzle 4, the nozzle cap 5 and the nozzle holder 6 and the nozzle 4 and the nozzle holder 6.

The nozzle cap 5 is also heated by the coolant flowing through the coolant space 4.10 formed by the outer surface of the nozzle 4 and the inner surface of the nozzle cap 5. chilled The nozzle cap 5 is heated primarily by the radiation from the arc or the plasma jet and the heated workpiece.

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

figure 5 shows a plasma cutting torch 1, the plasma cutting torch of figure 1 is similar, but in which a nozzle protective cap 8 is additionally arranged outside of the nozzle 4 . Bores 4.1 of the nozzle 4 and 8.1 of the nozzle protection cap 8 lie on a center line M. The inner surfaces of the nozzle protection cap 8 and a nozzle protection cap holder 9 form spaces 8.10 and 9.10 with the outer surfaces of the nozzle 4 and the nozzle holder 6, through which a secondary gas SG flows. This secondary gas emerges from the hole in the nozzle protection cap 8.1 and envelops the plasma jet (not shown) and ensures a defined atmosphere around it. In addition, the secondary gas SG protects the nozzle 4 and the nozzle protection cap 8 from arcs that can form between them and the workpiece. These are referred to as double arcs and can damage the nozzle 4. In particular when piercing the workpiece, the nozzle 4 and the nozzle protective cap 8 are heavily loaded by hot, molten, high-splashing material. The secondary gas SG, whose volume flow during piercing can be higher than during cutting, keeps the material spraying up away from the nozzle 4 and the nozzle protection cap 8 and thus protects against damage.

For the cooling of the electrode 2 and the nozzle 4 apply to the plasma cutting torch 1 according to figure 1 statements made. In principle, even with a plasma cutting torch 1 with secondary gas, the direct cooling of only the electrode 2 - as in figure 2 shown, and the indirect cooling of only the nozzle 4 - as in figure 3 shown - possible. The statements made for this also apply.

At the in figure 5 In the plasma cutting torch 1 shown, the nozzle protection cap 8 must also be cooled in addition to the electrode 2 and nozzle 4. The nozzle protection cap 8 is heated in particular by the radiation from the arc or the plasma jet and the heated workpiece. Particularly when piercing the workpiece, the nozzle protection cap 8 is thermally heavily stressed and heated up by the glowing material spraying up and must be cooled. For this reason, materials that are good heat conductors and electrically good conductors, usually metals such as silver, copper, aluminum, tin, zinc, iron, alloyed steel or a metallic alloy (e.g. brass), in which these metals are individually or are contained at least 50% in total.

The secondary gas SG first flows through the plasma cutting torch 1 before it passes through a first space 9.10 which is formed by the inner surfaces of the nozzle protective cap holder 9 and the nozzle protective cap 8 and the outer surfaces of the nozzle holder 6 and the nozzle 4. The first space 9 . The secondary gas routing part 7 can be designed in several parts.

In the secondary gas guide part 7 there are holes 7.1. However, there can also be openings, grooves or recesses through which the secondary gas SG flows. The secondary gas can be made to rotate by a corresponding arrangement of the bores 7.1, for example with a radial offset and/or an inclination to the center line M. This serves to stabilize the arc or the plasma jet.

After passing the secondary gas guide part 7, the secondary gas flows into an interior space 8.10, which is formed by the inner surface of the nozzle protection cap 8 and the outer surface of the nozzle 4, and then exits the bore 8.1 of the nozzle protection cap 8. When the arc or plasma jet is burning, the secondary gas hits it and can influence it.

The nozzle protection cap 8 is usually only cooled by the secondary gas SG. Gas cooling has the disadvantage that it is not effective and the required gas volume flow is very high in order to achieve acceptable cooling or heat dissipation. Gas flow rates of 5,000 to 11,000 l/h are often required here. At the same time, the volume flow of the secondary gas must be selected in such a way that the best cutting results are achieved. Volume flows that are too high, which are necessary for cooling, often worsen the cutting result.

In addition, the high gas consumption caused by large volume flows is uneconomical. This applies in particular when gases other than air, e.g. argon, nitrogen, hydrogen, oxygen or helium, are used.

These disadvantages are eliminated by using the insulating part designed as the secondary gas routing part 7 . Electrical insulation between the nozzle protective cap 8 and the nozzle 4 is achieved by using such an insulating part. The electrical insulation, in combination with the secondary gas SG, protects the nozzle 4 and the nozzle protection cap 8 from arcs that can form between them and the workpiece. These are referred to as double arcs and can damage the nozzle 4 or the nozzle protection cap 8.

At the same time, heat is transferred between the nozzle protective cap 8 and the nozzle 4 from the warmer to the colder component, in this case from the nozzle protective cap 8 to the nozzle 4, via the insulating part, which is a good conductor of heat and is designed as a secondary gas guide part 7 . The secondary gas guide part 7 is in contact with the nozzle protection cap 8 and the nozzle 4 by touch. In this exemplary embodiment, this takes place via annular surfaces 8.2 of the nozzle protection cap 8 and 7.4 of the secondary gas routing part 7 and the annular surfaces 7.5 of the secondary gas routing part 7 and 4.4 of the nozzle 4. These are non-positive connections, with the nozzle protection cap 8 being held in place with the aid of the nozzle protection cap holder 9, which is an internal thread 9.20 on an external thread 11.20 a recording 11 is screwed. This is pressed upwards against the secondary gas routing part 7 and against the nozzle 4 .

In this way, the heat is conducted from the nozzle protection cap 8 to the nozzle 4 and is thus cooled. The nozzle 4 in turn, as described in the figure 1 explained, indirectly cooled.

6 shows the structure of a plasma cutting torch 1 as in 4 , In which, however, a nozzle protection cap 8 is additionally arranged outside of the nozzle cap 5 .

Bores 4.1 of the nozzle 4 and 8.1 of the nozzle protection cap 8 lie on a center line M. The inner surfaces of the nozzle protection cap 8 and the nozzle protection cap holder 9 form spaces 8.10 and 9.10 with the outer surfaces of the nozzle cap 5 and the nozzle 4, through which a secondary gas SG can flow. The secondary gas emerges from the bore 8.1 of the nozzle protection cap 8, envelops the plasma jet (not shown) and ensures a defined atmosphere around the same. In addition, the secondary gas SG protects the nozzle 4, nozzle cap 5 and nozzle protection cap 8 from arcs that can form between them and a workpiece (not shown). These are referred to as double arcs and can damage the nozzle 4, nozzle cap 5 and nozzle protection cap 8. In particular when piercing a workpiece, the nozzle 4, the nozzle cap 5 and the nozzle protection cap 8 are heavily loaded by hot material spraying up. The secondary gas SG, whose volume flow during piercing can be higher than during cutting, keeps the material spraying up from the nozzle 4, the nozzle cap 5 and the nozzle protection cap 8 and thus protects it from damage.

For the cooling of the electrode 2, the nozzle 4 and the nozzle cap 5 apply in the description of 4 statements made.

The nozzle protection cap 8 is heated in particular by the radiation from the arc or the plasma jet and the heated workpiece. Particularly when piercing the workpiece, the nozzle protection cap 8 is thermally heavily stressed and heated up by the glowing material spraying up and must be cooled. For this reason, heat and electrically well-conducting materials, usually metals, for example copper, aluminum, tin, zinc, iron or alloys containing at least one of these metals, are used for this purpose.

The secondary gas SG first flows through the plasma torch 1 before it passes through a space 9.10 formed by the inner surfaces of the nozzle protective cap holder 9 and the nozzle protective cap 8 and the outer surfaces of a nozzle holder 6 and the nozzle cap 5. The space 9 .

In the secondary gas guide part 7 there are holes 7.1. However, there can also be openings, grooves or recesses through which the secondary gas SG flows. The secondary gas SG can be made to rotate by means of a corresponding arrangement of these bores 7.1, which have a radial offset and/or are arranged radially with an inclination to the center line M, for example. This serves to stabilize the arc or the plasma jet.

After passing the secondary gas guide part 7, the secondary gas SG flows into the space (interior) 8.10, which is formed by the inner surface of the nozzle protection cap 8 and the outer surface of the nozzle cap 5 and the nozzle 4, and then exits from the bore 8.1 of the nozzle protection cap 8. When the arc or plasma jet is burning, the secondary gas SG hits it and can influence it.

The nozzle protection cap 8 is usually only cooled by the secondary gas SG. Gas cooling has the disadvantage that it is not effective and the required gas volume flow is very high in order to achieve acceptable cooling or heat dissipation. Gas flow rates of 5,000 to 11,000 l/h are often required here. At the same time, the volume flow of the secondary gas must be selected in such a way that the best cutting results are achieved. Volume flows that are too high, which are necessary for cooling, often worsen the cutting result. In addition, the high gas consumption caused by large volume flows is uneconomical. This applies in particular when gases other than air, for example argon, nitrogen, hydrogen, oxygen or helium, are used. These disadvantages are eliminated by using the insulating part designed as a secondary gas routing part 7 . By using such an insulating part, the electrical insulation between the nozzle protection cap 8 and the nozzle cap 5 and thus also the nozzle 4 is achieved. The electrical insulation, in combination with the secondary gas SG, protects the nozzle 4, the nozzle cap 5 and the nozzle protection cap 8 from arcs that can form between them and a workpiece (not shown). These are called double arcs and can damage the tip, tip cap, and tip guard.

At the same time, heat is transferred between the nozzle protection cap 8 and nozzle cap 5 from the warmer to the colder component, in this case from the nozzle protection cap 8 to the nozzle cap 5, via the insulating part which is a good conductor of heat and is designed as a secondary gas routing part 7 . The secondary gas guiding part 7 is in contact with the nozzle protection cap 8 and the nozzle cap 5 by touch. In this exemplary embodiment, this is achieved by annular surfaces 8.2 of the nozzle protection cap 8 and 7.4 of the secondary gas routing part 7 and the annular surfaces 7.5 of the secondary gas routing part 7 and 5.3 of the nozzle cap 5. In this example, the connections are non-positive, with the nozzle protection cap 8 being held in place with the aid of the nozzle protection cap holder 9 is screwed to an external thread 11.20 of a receptacle 11 with an internal thread 9.20. This is pressed upwards against the secondary gas guide part 7 for the secondary gas SG and against the nozzle cap 5 . This way the heat will be dissipated from the tip guard 8 directed towards the nozzle cap 5 and thus cooled. The nozzle cap 5 in turn, as in the description of 4 explained, chilled.

7 shows a plasma cutting torch 1, for which the embodiment according to FIG 6 statements made apply. In addition, the nozzle protection cap holder 9 is screwed with its internal thread 9.20 to the external thread 11.20 of the receptacle 11, which is designed as an insulating part. The receptacle 11 consists of an electrically non-conductive and heat-conductive material. Thus, heat is transferred from the nozzle protection cap holder 9, which it can receive, for example, from the nozzle protection cap 8, from a hot workpiece or from the arc radiation, via the internal thread 9.20 and the external thread 11.20 to the receptacle 11. The receptacle 11 has coolant passages 11.10 and 11.11 for the coolant supply (WV1) and coolant return (WR1), which are designed here as bores. The coolant flows through this and thus cools the receptacle 11. This further improves the cooling of the nozzle protection cap holder 9. The heat is transferred from the nozzle protective cap 8 via its contact surface 8.3, which is designed as a circular ring surface, to a contact surface 9.1, which is also designed as a circular ring surface, on the nozzle protective cap holder 9. In this example, the contact surfaces 8.3 and 9.1 touch one another in a non-positive manner, with the nozzle protective cap 8 being screwed to the external thread 11.20 of the receptacle 11 with the aid of the nozzle protective cap holder 9 with the internal thread 9.20. This is pressed upwards against the secondary gas routing part 7 and the nozzle protection cap holder 9 against the nozzle protection cap 8 . In the present example, the receptacle 11 is made of ceramic. Aluminum nitride, which has very good thermal conductivity (approx. 180 W/(m ^∗ K)) and high specific electrical resistance (approx. 10 ¹² Ω ^∗ cm), is particularly suitable.

Coolant is simultaneously guided through coolant spaces 6.10 and 6.11 of the nozzle holder 6 to the nozzle 4 and nozzle cap 5 and cools them.

8 shows an embodiment of a plasma torch 1, which is that of 7 resembles. In principle, this also applies to the embodiments according to FIG 6 and 7 statements made. However, it contains a different embodiment of the insulating part designed as a receptacle 11 for the nozzle protection cap holder 9 . In this example, the receptacle 11 consists of two parts, with an outer part 11.1 consisting of an electrically non-conductive and heat-conductive material and an inner part 11.2 consisting of an electrically highly conductive and heat-conductive material.

The nozzle protection cap holder 9 is screwed with its internal thread 9.20 to the external thread 11.20 of part 11.1 of receptacle 11.

The electrically non-conductive and thermally highly conductive material is made of ceramic, for example aluminum nitride, which has very good thermal conductivity (approx. 180 W/(m ^* K)) and a high specific electrical resistance of approx. 10 ¹² Ω ^* cm. The material with good electrical and thermal conductivity is a metal here, for example copper, aluminum, tin, zinc, alloyed steel or alloys (for example brass) containing at least one of these metals.

In general, it is advantageous if the material with good electrical and thermal conductivity has a thermal conductivity of at least 40 W/(m ^∗ K)Ω and a specific electrical resistance of no more than 0.01 Ω ^∗ cm. In particular, it can be provided that the material with good electrical and thermal conductivity has a thermal conductivity of at least 60 W/(m ^* K), better at least 90 W/(m ^* K) and preferably 120 W/(m ^* K). . Even more preferably, the material with good electrical and thermal conductivity properties has a thermal conductivity of at least 150 W/(m ^* K), better still at least 200 W/(m ^* K) and preferably at least 300 W/(m ^* K). As an alternative or in addition, it can be provided that the material, which conducts electricity and heat well, is a metal, such as silver, copper, aluminum, tin, zinc, iron, alloyed steel or a metallic alloy (e.g. brass) that contains at least 50% of these metals individually or in total.

The use of two different materials has the advantage that for the more complicated part, in which different shapes are required, for example different bores, recesses, grooves, openings etc., the material can be used which can be machined more simply and cheaply. In this embodiment, this is a metal that is easier to machine than ceramic. Both parts (11.1 and 11.2) are non-positively connected by being pressed together and touching one another, as a result of which good heat transfer is achieved between the cylindrical contact surfaces 11.5 and 11.6 of the two parts 11.1 and 11.2. The part 11.2 of the recording 11 has coolant passages 11.10 and 11.11 for the coolant supply (WV1) and coolant return (WR1), which are designed here as bores. The coolant flows through these and thus cools.

How based on the 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 insulation between at least two electrically conductive components of the plasma torch, wherein it consists of at least two parts, one of the parts being made of an electrically non-conductive and heat a good conductive material and the other or another of the parts consists of a good electrical and heat conductive material.

figure 9 shows another embodiment of a plasma cutting torch 1 according to the present invention, which is principally the one shown in FIG figure 8 shown embodiment is similar. Thus also apply to the embodiments according to FIG figures 6 , 7 and 8th statements made. However, another embodiment variant of the insulating part designed as a receptacle 11 for the nozzle protection cap holder 9 is shown. The receptacle 11 consists of two parts, in which case the outer part 11.1, in contrast to the one in figure 8 shown Embodiment consists of an electrically highly conductive and thermally conductive material (e.g. metal) and the inner part 11.2 consists of an electrically non-conductive and thermally conductive material (e.g. ceramics).

The nozzle protection cap holder 9 with its internal thread 9.20 is screwed to the external thread 11.20 of part 11.1 of receptacle 11.

The advantage of this embodiment is that the external thread can be made in the metallic material used for the part 11.1 and not in the ceramic, which is more difficult to machine.

the Figures 10 to 13 show (further) different embodiments of an insulating part designed as a plasma gas guide part 3 for the plasma gas PG Figures 1 to 9 shown, wherein the respective figure with the letter "a" shows a longitudinal section and the respective figure with the letter "b" shows a partially sectioned side view.

That in the Figures 10a and 10b The plasma gas guide part 3 shown is made of an electrically non-conductive and thermally highly conductive material, here by way of example made of ceramic. Aluminum nitride, which has very good thermal conductivity (approx. 180 W/(m ^∗ K)) and high specific electrical resistance (approx. 10 ¹² Ω ^∗ cm), is particularly suitable. The associated advantages when used in a plasma cutting torch 1, such as better cooling, reduction in mechanical stresses, simpler structure, are already above in the description of the Figures 1 to 4 mentioned and explained.

In the plasma gas guide part 3 there are radially arranged bores 3.1 which, for example, can be offset radially and/or inclined radially to the center line M and allow a plasma gas PG to rotate in the plasma cutting torch. If the plasma gas guide part 3 in the When the plasma cutting torch 1 is installed, its contact surface 3.6 (here for example a cylindrical outer surface) is in contact with the contact surface 4.3 (here for example a cylindrical inner surface) of the nozzle 4, its contact surface 3.5 (here for example a cylindrical inner surface) with the contact surface 2.3 (here for example a cylindrical Outer surface) of the electrode 2 and its contact surface 3.7 (here, for example, a circular surface) with the contact surface 4.5 (here, for example, a circular surface) of the nozzle 4 by touching in contact ( Figures 1 to 9 ). In the contact surface 3.6 there are grooves 3.8. These guide the plasma gas PG to the bores 3.1 before it is guided through them into an interior space 4.2 of the nozzle 4, in which the electrode 2 is arranged.

the Figures 11a and 11b show a plasma gas guide part 3, which consists of two parts. A first part 3.2 consists of an electrically non-conductive and heat-conductive material, while a second part 3.3 consists of an electrically highly conductive and heat-conductive material.

Ceramic is used here as an example for part 3.2 of the plasma gas guide part 3, again as an example aluminum nitride, which has very good thermal conductivity (approx. 180 W/(m ^* K)) and a high specific electrical resistance (10 ¹² Ω ^* cm). . For part 3.3 of the secondary gas routing part 3, a metal such as silver, copper, aluminum, tin, zinc, iron, alloyed steel or a metallic alloy (e.g. brass) is used here, in which these metals are used individually or in total at least are used to 50%.

If, for example, copper is used for the part 3.3, the thermal conductivity of the plasma gas guide part 3 is greater than if it were made only of electrically non-conductive and heat-conductive material, such as aluminum nitride. Depending on its purity, copper has a higher thermal conductivity (max. approx. 390 W/(m ^∗ K)) than aluminum nitride (approx. 180 W/(m ^∗ K)), which is currently considered one of the best heat conductive and at the same time not a good electrical conductive material. Aluminum nitride with a thermal conductivity of 220 W/(m ^* K) is now also available.

Due to the better thermal conductivity, this leads to an even better heat exchange between the nozzle 4 and the electrode 2 of the plasma cutting torch 1 according to FIG Figures 1 to 9 .

In the simplest case, the parts 3.2 and 3.3 are connected by sliding the contact surfaces 3.21 and 3.31 over one another.

The parts 3.2 and 3.3 can also be non-positively connected by the contact surfaces 3.20 with 3.30, 3.21 with 3.31 and 3.22 to 3.32 which are pressed against one another and are opposite and touching. The contact surfaces 3.20, 3.21 and 3.22 are contact surfaces of part 3.2 and the contact surfaces 3.30, 3.31 and 3.32 are contact surfaces of part 3.3. The cylindrical contact surfaces 3.31 (cylindrical outer surface of part 3.3) and 3.21 (cylindrical inner surface of part 3.2) form a non-positive connection by being pressed together. Here, an interference fit DIN EN ISO 286 (e.g. H7/n6; H7/m6) is used between the cylindrical inner and outer surfaces.

There is also the possibility of connecting the two parts (3.2 and 3.3) to one another by positive locking, by soldering and/or by gluing and/or by a thermal process.

Since the mechanical processing of the ceramic material is usually more difficult than that of a metal, the processing effort is reduced. Here, for example, six bores 3.1 are made in the metallic part 3.3, which have a radial offset a1 and are distributed equidistantly at the angle α1 on the circumference of the plasma gas duct. There are too A wide variety of shapes, such as grooves, recesses, bores, etc., can be produced more easily if they are made in the metal.

the Figures 12a and 12b show a plasma gas guide part 3, which consists of two parts, with a first part 3.2 consisting of an electrically non-conductive and thermally well conductive material, while a second part 3.3 consists of an electrically non-conductive and thermally non-conductive material.

For the part 3.2 of the plasma gas guide part 3, ceramic is used as an example, again as an example aluminum nitride, which has a very good thermal conductivity (approx. 180 W/(m ^* K)) and a high specific electrical resistance (approx. 10 ¹² Ω ^* cm). , used. A plastic, for example PEEK, PTFE (polytetrafluoroethene), Torlon, polyamideimide (PAI), polyimide (PI), which has a high temperature resistance (at least 200° C.) and a high specific electrical resistance, can be used for part 3.3 of the plasma gas guide part 3 (at least 10 ⁶ , better at least 10 ¹⁰ Ω ^∗ cm) can be used.

In the simplest case, the parts 3.2 and 3.3 are connected by sliding the contact surfaces 3.21 and 3.31 over one another. You can also be non-positively connected by the pressed together, opposite and touching contact surfaces 3.20 with 3.30, 3.21 to 3.31 and 3.22 to 3.32. The cylindrical contact surfaces 3.31 (cylindrical outer surface of part 3.3) and 3.21 (cylindrical inner surface of part 3.2) then form the non-positive connection by being pressed together. Here, an interference fit DIN EN ISO 286 (e.g. H7/n6; H7/m6) is used between the cylindrical inner and outer surfaces. It is also possible to connect the two parts (3.2 and 3.3) to one another by positive locking and/or by gluing.

Since the mechanical processing of the ceramic material is usually more difficult than that of a plastic, the processing effort is reduced. For example, here are six holes 3.1 introduced into the plastic part 3.3, which have a radial offset a1 and are distributed equidistantly at the angle α1 on the circumference of the gas duct. A wide variety of shapes, such as grooves, recesses, bores, etc., can also be produced more easily if they are made in the plastic.

the Figures 13a and 13b show a plasma gas guide part 3 as in FIG figure 12 , except that a further part 3.4, which consists of a material with the same properties as the part 3.3, belongs to the plasma gas guide part 3.

Parts 3.2 and 3.4 can be connected to one another in the same way as parts 3.2 and 3.3, the contact surfaces 3.23 being connected to 3.43, 3.24 to 3.44 and 3.25 to 3.25.

Since the mechanical processing of the ceramic material is usually more difficult than that of a plastic, the processing effort is reduced and a wide variety of shapes, such as recesses, bores, etc., are easier to produce if they are made in the plastic.

the Figures 14a to 14b show another embodiment of a plasma gas guide part 3. The Figures 14c and 14d show a part 3.3 of the plasma gas guide part 3. The show the Figures 14a and 14c a longitudinal section and the Figures 14b and 14d a partially sectioned side view.

Part 3.2 consists of an electrically non-conductive and heat-conductive material, while part 3.3 consists of an electrically non-conductive and heat-non-conductive material.

In part 3.3 of the plasma gas guide part 3 there are radially arranged openings, here holes 3.1, which can be radially offset and/or radially inclined to the center line M and through which a plasma gas PG flows when the plasma gas guide part 3 is installed in the plasma cutting torch 1 (see Figures 1 to 9 ).

The part 3.3 has more radially arranged holes 3.9, which are larger than the holes 3.1. Six parts 3.2, shown here as a round pin as an example, are placed in these holes. These are distributed equidistantly on the circumference at an angle of a3=60°, which results between center lines M3.9.

If the plasma gas guide part 3 in the plasma cutting torch 1 after Figures 1 to 9 is installed, there are contact surfaces 3.61 (outer surfaces) of parts 3.2 (round pins) with a contact surface 4.3 (here a cylindrical inner surface) of the nozzle 4 and contact surfaces 3.51 (inner surface) of parts 3.2 (round pins) with the contact surface 2.3 (here a cylindrical outer surface) of the electrode 2 in contact by touch.

The parts 3.2 have a diameter d3 and a length 13 which is at least as large as half the difference between the diameters d10 and d20 of part 3.3. It is even better if the length 13 is slightly larger in order to obtain reliable contact between the contact surfaces of the round pins 3.2 and the nozzle 4 and the electrode 2. It is also advantageous if the surface of the contact surfaces 3.61 and 3.51 is not flat, but is adapted to the cylindrical outer surface (contact surface 2.3) of the electrode 2 and the cylindrical inner surface (contact surface 4.3) of the nozzle 4 in such a way that a form fit is created.

In the contact surface 3.6 there are grooves 3.8. These direct the plasma gas PG to the bores 3.1 before it is guided through them into the interior 4.2 of the nozzle 4, in which the electrode 2 is arranged.

Since the mechanical processing of the ceramic material is usually more difficult than that of a plastic, the processing effort is reduced and a wide variety of shapes, such as grooves, recesses, bores, etc., are easier to produce if they are made in the plastic. Despite the use of the same round pins, a wide variety of gas ducts can be produced inexpensively.

Furthermore, different thermal resistances or thermal conductivities of the plasma gas guide part 3 can be achieved by changing the number or the diameter of the round pins 3.2.

If the diameter and/or the number of round pins is/are reduced, the thermal resistance increases and the thermal conductivity decreases.

Since, depending on the power to be converted in the plasma torch or plasma cutting torch, from 500 W to 200 kW, there are very different thermal loads on the nozzles 4 and the electrode 2, adapting the thermal resistance is advantageous. For example, the manufacturing costs are reduced if fewer holes have to be drilled and fewer round pins have to be used.

the Figures 15 to 17 show (further) different embodiments of an insulating part designed as a secondary gas guide part 7 for a secondary gas SG, which is used in a plasma cutting torch 1, as is shown in FIGS Figures 6 to 9 shown, wherein each figure lettered "a" shows a partially sectional plan view and each figure lettered "b" shows a sectional side view.

the Figures 15a and 15b show a secondary gas guide part 7 for a secondary gas SG, as in a plasma cutting torch according to FIGS Figures 6 to 9 can be used.

That in the Figures 15a and 15b The secondary gas routing part 7 shown consists of an electrically non-conductive and thermally highly conductive material, here for example ceramic. Aluminum nitride, which has very good thermal conductivity (approx. 180 W/(m ^∗ K)) and high specific electrical resistance (approx. 10 ¹² Ω ^∗ cm), is particularly suitable here. Due to the low thermal resistance and the high thermal conductivity, high temperature differences can be avoided and the mechanical stresses caused by this in the plasma cutting torch can be reduced.

In the secondary gas guide part 7 there are radially arranged bores 7.1, which can also be radially or radially offset and/or radially inclined to the center line M and through which the secondary gas SG can flow or flows when the secondary gas guide part 7 is installed in the plasma cutting torch 1. In this example, 12 bores are radially offset by a dimension a11 and distributed equidistantly around the circumference, with the angle enclosed by the center points of the bores being denoted by α11. However, there can also be openings, grooves or recesses through which the secondary gas SG flows when the secondary gas guide part 7 is installed in the plasma cutting torch 1 . The secondary gas routing part 7 has two annular contact surfaces 7.4 and 7.5.

By using this secondary gas guide part 7, the electrical insulation between the nozzle cap 8 and the nozzle cap 5 and thus also the nozzle 4 of the Figures 6 to 9 plasma cutting torch 1 shown is reached. The electrical insulation, in combination with the secondary gas, protects the nozzle 4, the nozzle cap 5 and the nozzle protection cap 8 from arcs that can form between them and the workpiece (not shown). These are referred to as double arcs and can damage the nozzle 4, nozzle cap 5 and nozzle protection cap 8.

At the same time, heat is transferred between the nozzle protection cap 8 and the nozzle cap 5 from the warmer to the colder component, in this case from the nozzle protection cap 8 to the nozzle cap 5, via the heat-conductive secondary gas guide part 7 Transfer insulating part. The secondary gas guiding part 7 is in contact with the nozzle protection cap 8 and the nozzle cap 5 by touch. This is done in this embodiment by annular surfaces 8.2 of the nozzle protection cap 8 and 7.4 of the secondary gas guide part 7 and annular surfaces 7.5 of the secondary gas guide part 7 and 5.3 of the nozzle cap 5, which, as in the Figures 6 to 9 represented, touch.

the Figures 16a and 16b also show a secondary gas routing 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 heat conductivity, while a second part 7.3 consists of a material with good electrical conductivity and heat conductivity.

For part 7.2 of the secondary gas routing part 7, ceramic is again used as an example of aluminum nitride, which has very good thermal conductivity (approx. 180 W/(m ^* K)) and a high specific electrical resistance (approx. 10 ¹² Ω ^* cm). used. For part 7.3 of the secondary gas routing part 7, a metal such as silver, copper, aluminum, tin, zinc, iron, alloyed steel or a metallic alloy (e.g. brass) is used here, in which these metals are used individually or in total at least are used to 50%.

If, for example, copper is used for the part 7.3, the thermal conductivity of the secondary gas routing part 7 is greater than if it were made only of electrically non-conductive and heat-conductive material, such as aluminum nitride. Depending on its purity, copper has a higher thermal conductivity (max. approx. 390 W/(m ^∗ K)) than aluminum nitride (approx. 180 W/(m ^∗ K)), which is currently one of the best thermally conductive and at the same time non-electrical good conductive materials. Due to the better conductivity, this leads to an even better heat exchange between the nozzle protective cap 8 and the nozzle cap 5 of the plasma cutting torch 1 of FIG Figures 6 to 9 .

In the simplest case, parts 7.2 and 7.3 are connected by sliding contact surfaces 7.21 and 7.31 over one another.

The parts 7.2 and 7.3 can also be non-positively connected by the contact surfaces 7.20 with 7.30, 7.21 with 7.31 and 7.22 with 7.32 which are pressed against one another and lie opposite one another and touch. The contact surfaces 7.20, 7.21 and 7.22 are contact surfaces of part 7.2 and the contact surfaces 7.30, 7.31 and 7.32 are contact surfaces of part 7.3. The cylindrical contact surfaces 7.31 (cylindrical outer surface of part 7.3) and 7.21 (cylindrical inner surface of part 7.2) form a non-positive connection by being pressed together. Here, an interference fit DIN EN ISO 286 (e.g. H7/n6; H/m6) is used between the cylindrical inner and outer surfaces.

There is also the possibility of connecting the two parts to one another by positive locking, by soldering and/or gluing.

Since the mechanical processing of the ceramic material is usually more difficult than that of a metal, the processing effort is reduced. Here, for example, twelve bores 7.1 are made of metal in part 7.3, which have a radial offset a11 and are distributed equidistantly at an angle α11 on the circumference of the gas duct. A wide variety of shapes, such as grooves, recesses, bores, etc., can also be produced more easily if they are made in the metal.

the Figures 17a and 17b also show a secondary gas routing part 7 for a secondary gas SG, which consists of two parts. In contrast to the embodiment according to the figure 16 Here, a first part 7.2 consists of an electrically well conductive and heat conductive material and a second part 7.3 consists of an electrically non-conductive and heat conductive material. Otherwise, the same comments apply as for the Figures 16a and 6b.

In the 18a, 18b , 18c and 18d is a further embodiment of a secondary gas guide part 7 for a secondary gas SG, which is in a plasma cutting torch according to Figures 6 to 9 can be used, shown.

the 18a shows a top view and the Figure 18b and 18c sectional side views of different embodiments of the same. Figure 18d shows a part 7.3 of the secondary gas routing part 7 made of electrically non-conductive and heat non-conductive material.

In part 7.3 of the secondary gas guide part 7 there are radially arranged bores 7.1, which can also be radially or radially offset and/or radially inclined to the center line M and through which the secondary gas SG can flow when the secondary gas guide part 7 is installed in the plasma cutting torch 1. In this example, twelve bores are radially offset by a dimension a11 and are distributed equidistantly around the circumference, with the angle enclosed by the center points of the bores being denoted by α11 (here, for example, 30°). However, there can also be openings, grooves or recesses through which the secondary gas SG flows when the secondary gas guide part 7 enters the plasma cutting torch 1 (see, for example, Figures 6 to 9 ) is installed.

Figure 18d shows that in this example the part 7.3 has twelve further axially arranged bores 7.9 which are larger than the bores or openings 7.1.

In the Figures 18a and 18b twelve parts 7.2, which are shown here as round pins as examples, are introduced into these bores 7.9. The round pins 7.2 consist of an electrically non-conductive and heat-conductive material, while the part 7.3 consists of an electrically non-conductive and heat-non-conductive material.

If the secondary gas guide part 7 in the plasma cutting torch 1 according to Figures 6 to 9 installed, contact surfaces 7.51 of the round pins 7.2 are in contact with a contact surface 5.3 (here, for example, an annular surface) of the nozzle cap 5 and contact surfaces 7.41 of the round pins 7.2 with a contact surface 8.2 (here, for example, an annular surface) of the nozzle protection cap by touching ( Figures 6 to 9 ).

The parts 7.2 have a diameter d7 and a length l7 which is at least as large as the width b of the part 7.3. It is even better if the length 17 is slightly larger in order to obtain reliable contact between the contact surfaces of the round pins 7.2 and the nozzle cap 5 and the nozzle protection cap 8.

the 18c shows another embodiment of the secondary gas guiding part 7 for secondary gas. In this case, two parts 7.2 and 7.6, which are given as round pins by way of example, are introduced into each bore 7.9. The part 7.3 consists of an electrically non-conductive and thermally non-conductive material, the round pins 7.2 consist of an electrically non-conductive and heat-conductive material and the round pins 7.6 consist of an electrically highly conductive and heat-conductive material.

If the secondary gas guide part 7 in the plasma cutting torch 1 according to Figures 6 to 9 installed, contact surfaces 7.51 of the round pins 7.2 are in contact with a contact surface 5.3 (here for example the circular ring surface) of the nozzle cap 5 and contact surfaces 7.41 of the round pins 7.6 with a contact surface 8.2 (here for example the circular ring surface) of the nozzle protection cap 8 by touch (see also Figures 6 to 9 ). Both round pins 7.2 and 7.6 are connected by touch through their contact surfaces 7.42 and 7.52.

The parts 7.2 have a diameter d7 and a length 171. In this example, the parts 7.6 have the same diameter and a length l72, the sum of the lengths 171 and l72 being at least as large as the width b of the part 7.3. It is even better if the sum of the lengths is slightly larger, for example larger than 0.1 mm to obtain a secure contact between the contact surfaces 7.51 of the round pins 7.2 and the nozzle cap 5 and the contact surfaces 7.41 of the round pins 7.6 and the nozzle protection cap 8.

As the 18c and the associated description show, the present invention thus also relates in generalized form to an insulating part for a plasma torch, in particular a plasma cutting torch, for electrical insulation between at least two electrically conductive components of the plasma torch, the insulating part consisting of at least three parts, one of the parts consists of an electrically non-conductive and heat-conductive material, another of the parts consists of an electrically non-conductive and thermally non-conductive material and the other or another of the parts consists of an electrically well-conductive and heat-conductive material.

The in the Figures 15 to 18 Secondary gas guide parts 7 shown can also be used in a plasma cutting torch 1 according to figure 5 be used. The electrical insulation between the nozzle protective cap 8 and the nozzle 4 is realized there by using this secondary gas routing part 7 . In combination with the secondary gas SG, the electrical insulation protects the nozzle 4 and the nozzle protective cap 8 from arcs that can form between them and a workpiece. These are referred to as double arcs and can damage the nozzle 4 and the nozzle protection cap 8.

At the same time, heat is transferred between the nozzle protective cap 8 and the nozzle 4 from the warmer to the colder component, in this case from the nozzle protective cap 8 to the nozzle 4, via the insulating part designed as a secondary gas guide part 7 and having good thermal conductivity. The secondary gas guide part 7 is in contact with the nozzle protection cap 8 and the nozzle 4 by touch. This is done for those in the 15 , 16 and 17 shown embodiments of the secondary gas guide part 7 via the annular contact surfaces 8.2 of the nozzle protection cap 8 and the annular contact surfaces 7.4 of the secondary gas guide part 7 and the annular contact surfaces 7.5 of the secondary gas guide part 7 and the annular contact surfaces 4.4 of the nozzles 4, which, as in the figure 5 represented, touch.

In the embodiments of the Figure 18b and 18c In the secondary gas routing part 7 shown, heat is transferred via the annular contact surface 8.2 of the nozzle protection cap 8 and the contact surfaces 7.41 of the round pins 7.2 or 7.6 of the secondary gas routing part 7 from 7.51 of the round pins 7.2 to the contact surface 4.4 (here, for example, the circular ring surface) of the nozzle 4 by contact, as in the figure 5 shown.

the Figures 19a to 19d show sectional views of arrangements of a nozzle 4 and a secondary gas guide part 7 for a secondary gas SG according to special embodiments of the invention in FIGS Figures 15 to 18 . The comments on the figure 5 and to the Figures 15 to 18 .

while showing Figure 19a an arrangement with a secondary gas guide part 7 according to Figures 15a and 15b , Figure 19b an arrangement with a secondary gas routing part according to the 16a and 16b , Figure 19c an arrangement with a secondary gas routing part according to the Figure 17a and 17b and Figure 19d according to an arrangement with a secondary gas routing part Figures 18a and 18b .

In these exemplary embodiments, the secondary gas routing part 7 can be connected to the nozzle 4 in the simplest case by pushing them one over the other. However, they can also be connected in a positive and non-positive manner or by gluing. When using metal/metal and/or metal/ceramic at the connection point, soldering is also possible as a connection.

the Figures 20a to 20d show sectional views of arrangements of a nozzle cap 5 and a secondary gas guide part 7 for a secondary gas SG according to FIGS Figures 15 to 18 according to particular embodiments of the invention. The comments on the apply here Figures 6 to 9 and to the Figures 15 to 18 .

while showing Figure 20a an arrangement with a secondary gas routing part according to the Figures 15a and 15b ; Figure 20b an arrangement with a secondary gas routing part according to the 16a and 16b ; Figure 20c according to an arrangement with a secondary gas routing part Figure 17a and 17b and Figure 20d an arrangement with a secondary gas routing part according to the Figures 18a to 18d .

In these exemplary embodiments, the secondary gas routing part 7 can be connected to the nozzle cap 5 in the simplest case by sliding them over one another. However, they can also be connected in a positive and non-positive manner or by gluing. When using metal/metal and/or metal/ceramic at the connection point, soldering is also possible as a connection.

the Figures 21a to 21d show sectional views of arrangements of a nozzle protection cap 8 and a secondary gas routing part 7 for a secondary gas SG according to FIGS Figures 15 to 18 . The comments on the apply here Figures 5 to 9 and to the Figures 15 to 18 .

while showing Figure 21a an arrangement with a secondary gas routing part according to the Figures 15a and 15b ; Figure 21b an arrangement with a secondary gas routing part according to the 16a and 16b ; Figure 21c an arrangement with a secondary gas routing part according to the Figure 17a and 17b and Figure 21d an arrangement with a secondary gas routing part according to the Figures 18a to 18d .

In these exemplary embodiments, the secondary gas routing part 7 can be connected to the nozzle protection cap 8 in the simplest case by sliding them over one another. she but can also be connected in a positive and non-positive manner or by gluing. When using metal/metal and/or metal/ceramic at the connection point, soldering is also possible as a connection.

the Figures 22a and 22b show arrangements of an electrode 2 and a plasma gas guide part 3 for a plasma gas PG according to FIGS Figures 11 to 13 according to particular embodiments of the invention.

while showing 22a according to an arrangement with a plasma gas guide part Figure 11a and Figure 11b as well as the Figure 22b according to an arrangement with a plasma gas guide part 13a and Figure 13b .

In this exemplary embodiment, a contact surface 2.3 is, for example, a cylindrical outer surface of the electrode 2 and a contact surface 3.5 is a cylindrical inner surface of the plasma gas guide part 3. A loose fit with little play, for example H7/h6 according to DIN EN ISO 286, is preferably used here between the cylindrical inner and Outer surface used to on the one hand the nesting and on the other hand to realize a good contact and thus low thermal resistance and thus good heat transfer. The heat transfer can be improved by applying thermal paste to these contact surfaces. Then a fit with more play, for example H7/g6, can be used.

It is also possible to use an interference fit between the plasma gas guide part 3 and the electrode 2. This of course improves the heat transfer. The consequence of this, however, is that the electrode 2 and the plasma gas guide part 3 can only be exchanged together in the plasma cutting torch 1 .

the 23 shows an arrangement of an electrode 2 and a plasma gas guide part 3 for a plasma gas PG according to a particular embodiment of the present invention.

In this arrangement, contact surfaces 3.51 of the round pins 3.2 of the plasma gas guide part 3 are in contact with a contact surface 2.3 (here, for example, a cylindrical outer surface) of the electrode 2 (see also Figures 1 to 9 ).

The parts 3.2 have a diameter d3 and a length 13 which is at least as large as half the difference between the diameters d10 and d20 of part 3.3. It is even better if the length 13 is slightly larger in order to obtain reliable contact between the contact surfaces of the round pins 3.2 and the nozzle 4 and the electrode 2. It is also advantageous if the surface of the contact surfaces 3.61 and 3.51 is not flat, but is adapted to the cylindrical outer surface (contact surface 2.3) of the electrode 2 and the cylindrical inner surface (contact surface 4.3) of the nozzle in such a way that a form fit is created.

The arrangements of wearing parts and the insulating part or the gas routing part are only listed as examples. Of course, other combinations, such as nozzle and gas guide part, are also possible.

If in the preceding description reference was made to cooling liquid or the like, this is intended to mean a cooling medium in general.

In the foregoing description, among other things, arrangements and complete plasma torches are described. It is clear to the person skilled in the art that the invention can also consist of sub-combinations and individual parts, such as components or wearing parts. Protection is therefore explicitly claimed for this.

• "Elektrisch gut leitend" soll bedeuten, dass der spezifische elektrische Widerstand maximal 0,01 Ω^∗cm beträgt.
• "Elektrisch nicht leitend" soll bedeuten, dass der spezifische Widerstand minimal 10⁶ Ω^∗cm, besser mindestens 10¹⁰ Ω^∗cm beträgt und/oder das die Spannungsdurchschlagsfestigkeit mindestens 7 kV/mm, besser mindestens 10 kV/mm beträgt.
• "Wärme gut leitend" soll bedeuten, dass die Wärmeleitfähigkeit mindestens 40 W/(m^∗K), besser mindestens 60 W/(m^∗K), noch besser mindestens 90 W/(m^∗K)beträgt.
• "Wärme gut leitend" soll bedeuten, dass die Wärmeleitfähigkeit mindestens 120 W/(m^∗K), besser mindestens 150 W/(m^∗K), noch besser mindestens 180 W/(m^∗K) beträgt.
• Schließlich soll "Wärme gut leitend" insbesondere für Metalle bedeuten, dass die Wärmeleitfähigkeit mindestens 200 W/(m^∗K), besser mindestens 300 W/(m^∗K) beträgt.

Finally, a few definitions that should apply to the entire previous description:

• "Electrically well conductive" should mean that the specific electrical resistance is a maximum of 0.01 Ω ^∗ cm.
• "Electrically non-conductive" is intended to mean that the specific resistance is at least 10 ⁶ Ω ^* cm, better at least 10 ¹⁰ Ω ^* cm and/or that the dielectric strength is at least 7 kV/mm, better at least 10 kV/mm.
• "Good heat conductor" is intended to mean that the thermal conductivity is at least 40 W/(m ^* K), better at least 60 W/(m ^* K), even better at least 90 W/(m ^* K).
• "Good heat conductor" 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 at least 180 W/(m ^* K).
• Finally, "good heat conductor" should mean, in particular for metals, that the thermal conductivity is at least 200 W/(m ^* K), better at least 300 W/(m ^* K).

REFERENCE LIST

1

plasma cutting torch

2

electrode

2.1

electrode holder

2.2

emissions use

2.3

contact surface

2.10

coolant space

3

plasma gas guide part

3.1

drilling

3.2

Part

3.3

Part

3.4

Part

3.5

contact surface

3.6

contact surface

3.7

contact surface

3.8

groove

3.9

drilling

3.20

contact surface

3.21

contact surface

3.22

contact surface

3.23

contact surface

3.24

contact surface

3.25

contact surface

3.30

contact surface

3.31

contact surface

3.32

contact surface

3.43

contact surface

3.44

contact surface

3.45

contact surface

3.51

contact surface

3.61

contact surface

4

jet

4.1

nozzle bore

4.2

inner space

4.3

contact surface

4.4

contact surface

4.5

contact surface

4.10

coolant space

4.20

external thread

5

nozzle cap

5.1

nozzle cap bore

5.3

contact surface

5.20

inner thread

6

nozzle holder

6.10

coolant space

6.11

coolant space

6.20

inner thread

6.21

external thread

7

secondary gas routing part

7.1

drilling

7.2

Part

7.3

Part

7.4

contact surface

7.5

contact surface

7.6

Part

7.9

drilling

7.20

contact surface

7.21

contact surface

7.22

contact surface

7.30

contact surface

7.31

contact surface

7.32

contact surface

7.41

contact surface

7.42

contact surface

7.51

contact surface

7.52

contact surface

8th

nozzle protection cap

8.1

nozzle guard hole

8.2

contact surface

8.3

contact surface

8.10

inner space

8.11

inner space

9

Nozzle Protection Cap Bracket

9.1

contact surface

9.10

inner space

9.20

inner thread

10

cooling tube

10.1

coolant space

11

recording

11.1

Part

11.2

Part

11.5

contact surface

11.6

contact surface

11.10

coolant passage

11.11

coolant passage

11.20

external thread

PG

plasma gas

SG

secondary gas

WR1

Coolant return 1

WR2

Coolant return 2

WV1

Coolant supply 1

WV2

Coolant supply 2

a1

radial offset

a11

radial offset

b

Broad

d3

diameter

d7

diameter

d10

outer diameter

d11

inner diameter

d15

diameter

d20

inner diameter

d21

outer diameter

d25

diameter

d30

inner diameter

d31

outer diameter

d60

outer diameter

l3

length

131

length

l32

length

17

length

l71

length

172

length

173

length

l2

length

M

centerline

M3.1

centerline

M3.2

centerline

M3.9

centerline

M7.1

centerline

M3.6

centerline

α1

angle

a3

angle

α7

angle

α11

angle

Claims (23)

1. Multi-part plasma-torch insulating part for electrical insulation 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; 11.1, 11.2), wherein one of the parts (3.2; 7.2; 11.1) consists of an electrically non-conductive and readily thermally conductive material and the other part or at least one other of the parts (3.3; 7.3; 11.2) consists of an electrically non-conductive and thermally non-conductive material, wherein the electrically non-conductive and readily thermally conductive material has a thermal conductivity of at least 40 W/(m*K), preferably at least 60 W/(m*K) and even 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 even more preferably at least 180 W/(m*K).
2. Plasma-torch insulating part according to Claim 1, characterized in that the part (3.2) of an electrically non-conductive and readily thermally conductive material has at least one surface acting as a contact surface (3.51, 3.61, 7.41, 7.51), which is in line with or projects beyond a directly adjacent surface of the part (3.3, 7.3) of an electrically non-conductive and thermally non-conductive material.
3. Multi-part plasma-torch insulating part for electrical insulation 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), wherein one of the parts (3.3; 7.3) consists of a readily electrically conductive and readily thermally conductive material and the other part (3.2; 7.2) or at least one other of the parts consists of an electrically non-conductive and readily thermally conductive material, wherein the readily electrically conductive and readily thermally conductive material has a thermal conductivity of at least 40 W/(m*K)Ω), preferably at least 60 W/(m*K) and even 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 even more preferably at least 180 W/(m*K), and an electrical resistivity of at most 0.01 Ω*cm and the electrically non-conductive and readily thermally conductive material has a thermal conductivity of at least 40 W/(m*K), preferably at least 60 W/(m*K) and even 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 even more preferably at least 180 W/(m*K).
4. Multi-part plasma-torch insulating part for electrical insulation 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), wherein one of the parts (7.6) consists of a readily electrically conductive and readily thermally conductive material, another one of the parts (7.2) consists of an electrically non-conductive and readily thermally conductive material and a further one of the parts (7.3) consists of an electrically non-conductive and thermally non-conductive material, wherein the readily electrically conductive and readily thermally conductive material has a thermal conductivity of at least 40 W/(m*K)Q and an electrical resistivity of at most 0.01 Ω*cm and the electrically non-conductive and readily thermally conductive material has a thermal conductivity of at least 40 W/(m*K), preferably at least 60 W/(m*K) and even 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 even more preferably at least 180 W/(m*K).
5. Plasma-torch insulating part according to one of the preceding claims, characterized in that the electrically non-conductive and readily thermally conductive material and/or the electrically non-conductive and thermally non-conductive material have an electrical resistivity of at least 10⁶ Ω*cm, preferably at least 10¹⁰ Ω*cm, and/or a dielectric strength of at least 7 kV/mm, preferably at least 10 kV/mm.
6. Plasma-torch insulating part according to one of the preceding claims, characterized in that the electrically non-conductive and readily thermally conductive material is a ceramic or plastic.
7. Plasma-torch insulating part according to Claim 2, or a claim directly or indirectly dependent thereon, characterized in that the electrically non-conductive and thermally non-conductive material has a thermal conductivity of at most 1 W/(m*K).
8. Plasma-torch insulating part according to one of the preceding claims, characterized in that the parts are connected to one another in a form-fitting, force-fitting or cohesive manner and/or by adhesive bonding or by a thermal method.
9. Plasma-torch insulating part according to one of the preceding claims, characterized in that it has at least one opening.
10. Plasma-torch insulating part according to one of the preceding claims, characterized in that it has at least one cutout or in that it has at least one groove (3.8) or that it is designed to conduct a gas, in particular a plasma, secondary or cooling gas.
11. Assembly comprising a plasma-torch electrode (2) or a plasma-torch nozzle (4) or a plasma-torch nozzle cap (5) or a plasma-torch protective nozzle cap (8) or a plasma-torch protective nozzle cap holder (9) and a plasma-torch insulating part according to one of the preceding claims.
12. Assembly according to Claim 11, characterized in that the plasma-torch insulating part is in direct contact with the plasma-torch electrode (2) and/or the plasma-torch nozzle (4) or the plasma-torch nozzle cap (5) or the plasma-torch protective nozzle cap (8) or the plasma-torch protective nozzle cap holder (9).
13. Assembly comprising a plasma-torch protective nozzle cap holder (9) mount (11) and a plasma-torch protective nozzle cap holder (9), wherein the plasma-torch protective nozzle cap holder (9) mount (11) is formed as a plasma-torch insulating part according to one of Claims 1 to 10.
14. Assembly comprising a plasma-torch electrode (2) and a plasma-torch nozzle (4), wherein a plasma-torch insulating part according to one of Claims 1 to 10, formed as a plasma gas conducting part (3), is arranged between the plasma-torch electrode (2) and the plasma-torch nozzle (4).
15. Assembly comprising a plasma-torch nozzle (4) and a plasma-torch protective nozzle cap (8), wherein a plasma-torch insulating part according to one of Claims 1 to 10, formed as a secondary gas conducting part (7), is arranged between the plasma-torch nozzle (4) and the plasma-torch protective nozzle cap (8).
16. Assembly comprising a plasma-torch nozzle cap (5) and a plasma-torch protective nozzle cap (8), wherein a plasma-torch insulating part according to one of Claims 1 to 10, formed as a secondary gas conducting part (7), is arranged between the plasma-torch nozzle cap (5) and the plasma-torch protective nozzle cap (8).
17. Plasma torch, in particular a plasma cutting torch (1), comprising at least one plasma-torch insulating part according to one of Claims 1 to 10.
18. Plasma torch according to Claim 17, characterized in that the plasma-torch insulating part or a part of the same consisting of an electrically non-conductive and readily thermally conductive material has at least one surface acting as a contact surface, which is in direct contact at least with a surface of a readily electrically conductive part of the plasma torch, wherein the readily electrically conductive component has an electrical resistivity of a maximum of 0.01 Ω*cm.
19. Plasma torch according to either of Claims 17 and 18, characterized in that the plasma-torch insulating part is a gas conducting part.
20. Plasma torch according to one of Claims 17 to 19, characterized in that the plasma-torch insulating part has at least one surface which is in direct contact with a cooling medium during operation.
21. Plasma torch, in particular a plasma cutting torch (1), comprising at least one assembly according to one of Claims 11 to 16.
22. Method for working a workpiece with a thermal plasma or for plasma cutting or for plasma welding, characterized in that a plasma torch according to one of Claims 16 to 21 is used.
23. Method according to Claim 22, characterized in that, in addition to the plasma jet, a laser beam of a laser is coupled into the plasma torch.

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