Plasma torch for coating surfaces

Abstract

The invention relates to a plasma torch (10) for coating surfaces, comprising a first component (12) and a second component (14), and media channels (20, 22) leading from the first component (12) to the second component (14) or from the second component (14) to the first component (12). The plasma torch (10) has a multi-seal element (24) arranged between the first component (12) and the second component (14), with which a plurality of the media channels (20, 22) are sealed.

Description

[0001] The invention relates to a plasma torch for coating surfaces according to the preamble of claim 1.

[0002] Plasma torches in accordance with the invention heat a gas mixture to over 10,000 °C using an arc. The material to be applied to the surface to be coated is sprayed into this hot plasma jet as a fine powder. The powder is melted in the plasma jet, heated to approximately 2,500 °C, and sprayed onto the surface at a speed of approximately 100 m / s.

[0003] In particular, the invention relates to a plasma torch which is suitable in its size and power for coating the running surfaces of cylinders of reciprocating internal combustion engines.

[0004] The engine blocks of modern reciprocating piston internal combustion engines are typically made of cast aluminum, which allows for low component weight combined with positive cooling properties. The running surfaces, especially in cast aluminum cylinders, are typically coated with a thin layer of a wear-resistant, harder material, also to achieve lower friction values ​​between piston and cylinder and the necessary abrasion resistance for long-term operation.

[0005] The challenge in building such plasma torches lies in managing the energy densities and temperature gradients that occur in very confined spaces. This particularly applies to plasma torches used for coating the running surfaces of cylinders, which therefore must be small enough to be used inside the cylinders.

[0006] Such plasma torches often have a complex design; in particular, they typically contain a number of media channels. This usually involves a gas / plasma channel through which the gas to be heated is guided, and usually also the plasma is generated by means of an arc ignited in this channel. Furthermore, the media channels of such a plasma torch typically include coolant channels. These are required to cool the components of the plasma torch to a temperature that is, in particular, low enough for the materials used.

[0007] Therefore, the plasma torches known from the prior art have a whole series of different sealing elements, such as O-rings, with which a media channel leading from one component of the plasma torch to another component of the plasma torch is sealed.

[0008] A corresponding prior art plasma torch is known, for example, from US Patent 4,506,136. The plasma torch features a whole series of different seals, which are also arranged at different levels. However, these seals each require a certain amount of space. This space requirement, however, conflicts with the desire to be able to build such plasma torches with the smallest possible external dimensions, for example, to coat the running surfaces of small-volume cylinders.

[0009] Plasma torches are therefore also known in practice that do not require sealing elements between the components surrounding the gas / plasma channel. While this allows for a more compact design of the plasma torch, the disadvantage is that such plasma torches result in an uncontrolled escape of plasma gas between the components through which the plasma channel passes. This uncontrolled escape of plasma gas reduces process stability. Furthermore, it leads to increased wear, particularly on the components between which the uncontrolled escape of plasma gas occurs.

[0010] The object of the invention is therefore to provide a plasma torch of the type in question in which uncontrolled escapes of media of any kind, in particular of plasma gas, are avoided, at least to a large extent, while at the same time having a design that is as compact as possible.

[0011] The object is achieved by a plasma torch having the features of independent claim 1. The features of the dependent claims relate to advantageous embodiments.

[0012] The plasma torch for coating surfaces comprises a first component and a second component. Furthermore, the plasma torch has media channels that lead from the first component into the second component or from the second component into the first component. In other words, the media channels are routed through an interface between the first component and the second component.

[0013] This object is achieved in particular by the plasma torch having at least one multiple sealing element arranged between the first component and the second component, with which a plurality of the media channels are sealed. It has been shown that the use of such a multiple sealing element allows for a significant reduction in installation space compared to a conventional design in which each media channel is sealed with a separate sealing element.

[0014] Advantageously, the plasma torch can have a third component and media channels leading from the first component into the third component or from the third component into the first component. In other words, these media channels are routed through an interface between the first component and the third component. The plasma torch has, in particular, an additional multiple sealing element arranged between the first component and the third component. A plurality of the media channels are sealed with the additional multiple sealing element. It has been shown that the use of such an additional multiple sealing element can further increase space savings.

[0015] In particular, the multiple sealing element and the further multiple sealing element can be arranged in different planes that are at least substantially parallel to each other. This allows for corresponding space savings within each of these planes, thus allowing the overall dimensions of the plasma torch to be reduced particularly effectively.

[0016] The plasma torch has in particular a power of more than 10 kW, preferably power between 12 kW and 20 kW and particularly preferably power of approximately 12 kW to 16 kW.

[0017] The size of the plasma torch is preferably designed so that it can be inserted into and still moved within cylinders with a maximum diameter of 100 mm, more preferably into cylinders with a maximum diameter of 80 mm, and especially preferably into cylinders with a maximum diameter of 75 mm. This results in a particularly compact plasma torch, where space savings are particularly important.

[0018] The dimensions extending at right angles to the longitudinal direction of the plasma torch, height and width, are each preferably a maximum of 50 mm, more preferably a maximum of 40 mm, and particularly preferably a maximum of 35 mm. The invention was specifically designed for a plasma torch with a height and width of 25 mm x 35 mm and a length of approximately 75 mm. During operation, the longitudinal direction of the plasma torch preferably corresponds to its insertion direction into a cylinder to be coated.

[0019] The first component can, in particular, be an insulating element. Such insulating elements are used in plasma torches of the type in question, in particular to electrically insulate live components from one another, which in particular carry the voltage for generating the arc used to generate the plasma. Such insulating elements are suitable for leading media channels through the insulating element into live components adjacent to the insulating element and out of these components. The insulating element can, in particular, be a plate-shaped insulating element, at least in some regions. A corresponding plate-shaped design of the insulating element enables comparatively large interfaces to the live components separated by the insulating element. This provides a comparatively large interface through which, for example, media channels can be led.

[0020] The second component and / or the third component can be a component that carries an electrical voltage. The voltage-carrying second and / or third component can, for example, be a nozzle plate of the plasma torch, which has outlet nozzles for the gas / plasma flow and / or other media. Alternatively and / or additionally, the voltage-carrying second and / or third component can be an electrode holder element in which an electrode for generating the arc is accommodated.

[0021] The second component and / or the third component can also be plate-shaped. Particularly in conjunction with a plate-shaped first component, this allows for the creation of a "sandwich-like" structure of a plasma torch, in which, in particular, a plate-shaped insulating element or a plate-shaped region of an insulating element is arranged between two plate-shaped voltage-carrying components. Such a structure can advantageously form the basis for a particularly compact plasma torch, the dimensions of which can be particularly effectively reduced through the use of the multiple sealing elements between the first and second and / or the second and third components.

[0022] The multiple sealing element and / or the additional multiple sealing element can each have a plurality of sealing areas surrounding the individual media channels sealed by the respective multiple sealing element. The multiple sealing element and / or the additional multiple sealing element can have sections that are part of two adjacent sealing areas, each surrounding a media channel. Such a design of the multiple sealing element corresponds to a design similar to a plurality of common sections of individual conventional sealing elements fused together, such as a plurality of fused-together O-rings. Such a multiple sealing element allows the realization of particularly small distances between the individual media channels sealed by the multiple sealing element.

[0023] The sealing areas can, in particular, surround the media channels in a circular shape. Circular sealing areas can encompass the largest possible cross-sectional area of ​​a media channel with a minimal sealing area length. The proportion of the area required for sealing areas between the components involved is thus minimized.

[0024] One of the media channels sealed by the multiple sealing element and / or the additional multiple sealing element can be a gas / plasma channel. The gas / plasma channel of a plasma torch of the type in question is typically located in the center or at least near the center of a plasma torch of the type in question. Accordingly, the sealing of the gas / plasma channel can be sensibly incorporated into the multiple sealing element for the purpose of saving space.

[0025] Furthermore, at least one of the media channels sealed by the multiple sealing element and / or the further multiple sealing element can be a coolant channel, in particular a cooling water channel. Coolant channels, in particular cooling water channels, have a comparatively large cross-section and can advantageously be guided through a first component designed as an insulating element into a live second and / or third component and out of these again into the first component. Therefore, for the purpose of saving space, it is expedient to also seal such coolant channels by means of the multiple sealing element or the further multiple sealing element. Advantageously, a majority of the media channels sealed by the multiple sealing element and / or the further multiple sealing element can be coolant channels, in particular cooling water channels.

[0026] Preferably, the media channels sealed by the multiple sealing element and / or the further multiple sealing element can be a gas / plasma channel and at least two coolant channels. In particular, the sealing areas sealing the coolant channels can be arranged around the sealing area surrounding the gas / plasma channel. This enables an overall space-saving arrangement with a gas / plasma channel advantageously located in the center of the plasma torch.

[0027] The sealing areas of the respective multiple sealing element surrounding the individual media channels can be arranged in a common plane. This advantageously allows a sandwich-like structure consisting of components and seals arranged between the components to be realized, particularly in conjunction with components that are plate-shaped, at least in some areas, thus resulting in an extremely compact plasma torch design.

[0028] The multiple sealing element and / or the additional multiple sealing element can have an elastically deformed cross-section. Such sealing elements with an elastically deformed cross-section have proven effective as sealing elements for use in plasma torches of the type in question.

[0029] The multiple sealing element and / or the additional multiple sealing element, in particular, has a circular cross-section in the undeformed state. The cross-sections of the multiple sealing elements can deviate from the circular ring shape, particularly in the transition areas between individual sealing areas, each of which surrounds a media channel. Sealing elements with a circular cross-section in the undeformed state are known and proven as O-rings. A corresponding sealing element can advantageously have the shape of a plurality of fused-together O-rings. In this way, a multiple sealing element can be created that combines the space savings enabled by the multiple sealing element with the proven sealing effect of O-rings.

[0030] Further practical embodiments of the invention are described below in conjunction with the drawings. They show: Fig. 1 a sectional view of an exemplary plasma torch, Fig. 2 a perspective view of the second component and the multiple sealing element of the plasma torch from Fig. 1, Fig. 3 a perspective view of the third component and the further multiple sealing element of the plasma torch from Fig. 1.

[0031] The exemplary plasma torch 10, we in the Fig. 1-3, a first component 12 is shown. This can be an insulating element, as in the example shown. The insulating element can, as in Fig. 1, may be plate-shaped in some areas. As shown in the example, the insulating element may have a T-shaped cross-section. In this way, the insulating element may form an insulating layer between the second component 14 and the third component 16 of the exemplary plasma torch 10 and, at the same time, form a connection side 18 of the plasma torch 10, on which media connections of the plasma torch 10 may be arranged.

[0032] The plasma torch 10 can have media channels 20, 22, as in the example shown. The media channels 20, 22 can be, as shown by way of example, a gas / plasma channel 20 and coolant channels 22. As in the example shown, the second component 14 can be designed as an electrode holding element and the third component 16 as a nozzle plate.

[0033] The media channels 20, 22 can lead from the first component 12 into the second component 14 or third component 16 or from the second component 14 or third component 16 to the first component 12. In the example shown, in particular a gas / plasma channel 20 leads from the second component 14 into the first component 12 and from there into the third component 16. The individual coolant channels 22 can, as shown by way of example, lead from the first component 12 into the second component 14 or the third component 16 and from the second component 14 or the third component 16 back into the first component 12. In this way, for example, the second and third components can be supplied with coolant via the first component.

[0034] As shown by way of example, the plasma torch can have a multiple sealing element 24 arranged between the first component 12 and the second component 14, and a further multiple sealing element 26 arranged between the first component 12 and the third component 16. As in the example shown, a plurality of media channels 20, 22 can each be sealed with the multiple sealing element 24 and the further multiple sealing element 26. As in the example shown, the multiple sealing element 24 and the further multiple sealing element 26 can each have a plurality of annular sealing regions, each surrounding one of the media channels 20, 22.

[0035] The gas / plasma channel 20 can be formed in the region of an electrode 28 by a plurality of parallel channels. These can be arranged distributed around the electrode 28, as in the example shown. As shown in particular in the Fig. 2, these individual channels are surrounded by a circular sealing area of ​​the multiple sealing element 24.

[0036] The multiple sealing element 24 and the further multiple sealing element 26 can, as in the example shown, each seal the gas / plasma channel 20 and a plurality of coolant channels 22. In this case, the sealing areas sealing the coolant channels 22 can, as in the example shown, in particular in the Fig. 2 and Fig. 3, the sealing area surrounding the gas / plasma channel 20 can be arranged. Such a configuration of the multiple sealing element 24 or the further multiple sealing element 26 enables the space-saving arrangements of the sealed media channels 20, 22 shown.

[0037] As in the example shown, an injector holder 30 for a powder injector (not shown) can be arranged on the plasma torch 10, by means of which metal powder can be injected into the plasma stream emerging from the gas / plasma channel 20.

[0038] The features of the invention disclosed in the present description, the drawings, and the claims may be essential, both individually and in any combination, for the realization of the invention in its various embodiments. The invention may be varied within the scope of the claims and taking into account the knowledge of the person skilled in the art. List of reference symbols 10 plasma torches 12 first component 14 second component 16 third component 18 Connection side 20 gas / plasma channel 22 coolant channels 24 multiple sealing element 26 additional multiple sealing elements 28 Electrode 30 injector holders QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] US 4,506,136

[0008]

Claims

[1] Plasma torch (10) for coating surfaces, comprising a first component (12) and a second component (14) and media channels (20, 22) leading from the first component (12) into the second component (14) or from the second component (14) into the first component (12), characterized by that the plasma torch (10) has a multiple sealing element (24) arranged between the first component (12) and the second component (14), with which a plurality of the media channels (20, 22) are sealed. [2] Plasma torch (10) according to claim 1, characterized by in that the plasma torch (10) has a third component (16) and media channels (20, 22) leading from the first component (12) into the third component (16) or from the third component (16) into the first component (12), wherein the plasma torch (10) has a further multiple sealing element (26) arranged between the first component (12) and the third component (16), with which a plurality of the media channels (20, 22) are sealed. [3] Plasma torch (10) according to claim 1 or 2, characterized by that the first component (12) is an insulating element, in particular one which is plate-shaped at least in some areas. [4] Plasma torch (10) according to one of the preceding claims, characterized by that the second component (14) and / or the third component (16) is a component, in particular a plate-shaped component, which carries an electrical voltage. [5] Plasma torch (10) according to one of the preceding claims, characterized by that the multiple sealing element (24) and / or the further multiple sealing element (26) each have a plurality of sealing areas surrounding the individual media channels (20, 22) sealed by means of the respective multiple sealing element (24, 26), in particular in a circular ring shape. [6] Plasma torch (10) according to one of the preceding claims, characterized bythat one of the media channels (20, 22) sealed by means of the multiple sealing element (24) and / or the further multiple sealing element (26) is a gas / plasma channel (20). [7] Plasma torch (10) according to one of the preceding claims, characterized by that at least one, preferably a plurality, of the media channels (20, 22) sealed by means of the multiple sealing element (24) and / or the further multiple sealing element (26) is a coolant channel (22). [8] Plasma torch (10) according to one of the preceding claims, characterized by that the media channels (20, 22) sealed by means of the multiple sealing element (24) and / or the further multiple sealing element (26) are a gas / plasma channel (20) and at least two coolant channels (22), in particular wherein the sealing regions sealing the coolant channels (22) are arranged around the sealing region surrounding the gas / plasma channel (20). [9] Plasma torch (10) according to one of the preceding claims, characterized by that the areas of the respective multiple sealing element (24, 26) surrounding the individual media channels (20, 22) are arranged in a common plane. [10] Plasma torch (10) according to one of the preceding claims, characterized by that the multiple sealing element (24) and / or the further multiple sealing element (26) has an elastically deformed, in particular annular, cross-section in the undeformed state.

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