EP2383361A1 - Device for coating substrates by means of high speed flame spraying - Google Patents

Abstract

The device comprises a combustion chamber (4), a primary fuel line (L1) for supplying liquid or gaseous fuel, a gas line for supplying oxidative gas, a secondary fuel line for supplying liquid or gaseous fuel, and another gas line for supplying gas. A nozzle body (7) is provided, which has a central opening or nozzle for supplying liquid fuel into the combustion chamber.

Description

The invention relates to a device for coating substrates by means of high-speed flame spraying according to the preamble of claim 1.

Devices of the type in question are known in various embodiments and are used for various purposes. They are used for example for the application of temperature-resistant and / or hard and / or abrasion-resistant and / or chemically resistant layers on surfaces of various substrates.

Devices are known from the prior art, which are operated with a gaseous fuel. Also known are devices that can be operated with liquid fuel. Generic devices usually have at least one connection for the fuel and another for an oxidative gas. In particular, in devices that are operated with a liquid fuel, an additional connection for the supply of compressed air can still be provided. However, all these known devices have the disadvantage that their application is limited.

In the DE 44 29 142 A1 a nozzle spray head for high velocity flame spraying of powdered materials is described. The nozzle spray head can be operated simultaneously with two fuels (diesel / fuel oil and a fuel gas), with diesel or fuel oil with a carbonization content above 0.5 wt .-% can be used as the main fuel. In order to achieve the cleanest possible combustion of the main fuel, an evaporation flame is generated by means of the fuel gas, which allows the same a pre-evaporation of the fuel oil and thus a coking-free combustion. The vaporization flame is generated in the direction of flow of the gases before the main flame. In order to enable residue-free combustion of the main fuel, both fuels must therefore always be supplied simultaneously.

The EP 0 458 018 A2 discloses a HVOF burner provided with a primary combustion chamber and a secondary combustion chamber. Both burners are operated with separate fuels. The primary combustion chamber serves to melt the spray material, while the molten spray material is accelerated in the subsequent secondary combustion chamber to supersonic speed, so that the molten spray material ultimately exits the burner with a high kinetic energy. Thus, this burner must always be operated simultaneously with both fuel gases.

Finally goes out of the US 4,375,954 A a burner operated with gas and oil in combination. This burner has an annular preheat chamber in which the oil is first heated by means of a fuel gas. Thereafter, the heated oil is passed via a central nozzle into the combustion chamber, where it is burned. However, this burner is not a coating device for applying layers to surfaces of substrates, but a conventional burner.

The invention aims to develop a device according to the preamble of claim 1 such that it is universally applicable by being operable in different modes.

For this purpose, a device according to claim 1 is provided according to the invention.

Preferred embodiments of the device are described in the dependent claims 2 to 15.

In a preferred embodiment, it is proposed that the outlet openings of the further fuel line are arranged on a circular line, wherein said outlet openings are arranged coaxially to the at least one outlet opening centrally into the combustion chamber. Such In any case, that is to say both in operation with one or the other fuel and in operation with both fuels, it is possible to produce a homogeneous and central combustion flame.

In a further, preferred embodiment of the device, it is proposed that the outlet openings of the at least one gas line are arranged on a circular line, which are arranged coaxially with the outlet opening centrally into the combustion chamber. This training favors on the one hand a homogeneous combustion flame and on the other hand a residue-free combustion.

In a further, preferred development, the device has a nozzle body adjoining the combustion chamber, which is inserted interchangeably into a connection body of the device, wherein the nozzle body is provided with outlet openings and the two fuel lines and the first gas line are connected to the nozzle body such that the combustion chamber, the media necessary for the operation of the device via the said outlet openings of the nozzle body can be fed. The advantage of this design is that the nozzle body is interchangeable, with the replacement of the nozzle body at the same time all outlet openings are emulated. This is particularly important because the respective body is exposed to very high loads in the region of the aforementioned outlet openings, which is accompanied by wear and leads to undesired removal of material and, if necessary, application of material in the area of the outlet openings. It is understood that this is undesirable and leads to an adverse burning behavior.

Fig.1

Die Vorrichtung zur Beschichtung von Substraten mittels Hochgeschwindigkeitsflammspritzen in einer Ansicht von hinten;

Fig. 2

die Vorrichtung in einem Schnitt entlang der Linie A-A in Fig. 1;

Fig. 3

die Vorrichtung in einem Schnitt entlang der Linie B-B in Fig. 1;

Fig. 4

die Vorrichtung in einem Schnitt entlang der Linie C-C in Fig. 1;

Fig. 5

die Vorrichtung in einem Schnitt entlang der Linie D-D in Fig. 1;

Fig. 6a

einen Düsenkörper in einer Ansicht von vorne;

Fig. 6b

den Düsenkörper in einem Schnitt entlang der Linie A-A in Fig. 6a, und

Fig. 6c

den Düsenkörper in einem Schnitt entlang der Linie B-B in Fig. 6a.

Hereinafter, a preferred embodiment of the invention will be explained in more detail with reference to drawings. In these drawings shows:

Fig.1

The device for coating substrates by means of high-speed flame spraying in a view from behind;

Fig. 2

the device in a section along the line AA in Fig. 1 ;

Fig. 3

the device in a section along the line BB in Fig. 1 ;

Fig. 4

the device in a section along the line CC in Fig. 1 ;

Fig. 5

the device in a section along the line DD in Fig. 1 ;

Fig. 6a

a nozzle body in a front view;

Fig. 6b

the nozzle body in a section along the line AA in Fig. 6a , and

Fig. 6c

the nozzle body in a section along the line BB in Fig. 6a ,

The Fig. 1 shows the device for coating substrates by means of high-speed flame spraying in a view from the back. The device consists essentially of the actual burner, as well as means for supplying the to be melted and applied coating material. From the illustration according to Fig. 1 it can be seen that the device is provided on the back with a plurality of terminals, via which on the one hand the necessary for the operation of the burner media can be supplied. In addition, one connection is provided for a pressure sensor and another for an ignition unit. It is understood that the number and arrangement of the terminals may vary. In the present example, the ports A1 to A9 are provided for the supply of the following media: A1 liquid fuel, A2 oxygen, A3 oxygen optional, A4 nitrogen, A5 gaseous fuel, A6 cooling water on, A7 cooling water off, A8 powder, A9 powder. Of course, other liquid or gaseous media can be supplied via the ports A1 to A7 instead of the aforementioned media. The connection A10 is provided for the ignition unit and the connection A11 for the said pressure sensor.

The Fig. 2 shows a simplified representation of the device in a longitudinal section along the line AA in Fig. 1 , Since the basic structure and the operation of generic devices is known, not all elements will be discussed below. Such devices are known in the art in particular under the name HVOF (High Velocity Oxygen Fuel) burner or device.

The device comprises a main body 1, on the rear side of which a connecting body 2 is attached. Within the base body 1, a hollow body 3 is arranged, which forms the actual combustion chamber 4 in the interior. The tubular outlet of the hollow body 3 is connected to a pipe nozzle 5, which forms the end of the outlet 6 of the device. On the side facing the combustion chamber 4, a nozzle body 7 is inserted centrally into the connection body 2. The nozzle body 7 is exchangeably received in the connecting body 2, wherein it is fixed in the axial direction by means of an annular body 8. For this purpose, the ring body 8 is provided with an annular extension 9, which comes in the axial direction of the nozzle body 7 to the plant. The annular body 8 in turn lays in the axial direction on a shoulder of the hollow body 3. The annular body 8 is provided with two axial through holes 10, 11 which are aligned with one associated, in the connection body recessed line L10, L11.

In order to fix the connecting body 2 to the main body 1 and further elements such as the nozzle body 7 and the annular body 8 in the axial direction to positioning and fixing a union nut 21 is arranged on the base body 1, whose internal thread is intended to attack an external thread of the terminal body 2 and when tightening pulls the connector body 2 in the axial direction against the base body 1. Another union nut 22 is arranged at the front end of the base body 1, by means of which the pipe nozzle 5 is loaded together with the hollow body 3 and the ring body 8 in the direction of the connection body 2. In any case, the device can be quickly and easily assembled and also disassembled by the provision of two union nuts 21, 22 in the manner shown. This has the particular advantage that any Wear parts such as the hollow body 3, the pipe nozzle 5 or the nozzle body 7 can be replaced quickly and easily. Thus, after loosening the union nut 21, the connection body 2 can be removed from the main body 1 and the nozzle body 7 removed and possibly replaced or replaced.

As can be seen, leads from each terminal a line into the interior of the connector body 2. From the fuel port A1 leads a fuel line L1 centrally through the connector body 2 to the nozzle body 7, which latter the targeted feeding of the necessary for the operation of the burner media the combustion chamber 4 is used. The nozzle body 7 is then based on the Figures 6a-6c explained in more detail. In order to control the supply of the fuel in the fuel line L1, a flow regulator 24 is provided. With the flow controller 24, shown schematically on the one hand, the combustion chamber 4 per unit time supplied fuel quantity can be adjusted. On the other hand, the flow regulator 24 also serves to open or close the associated fuel line L1.

On the connected to the respective cooling water connection A6, A7 lines L6, L7 will not be discussed in more detail, since such the cooling of the thermally highly stressed parts serving cooling water lines are known. The port A10 is connected to the combustion chamber via an axial line L10. The connection A10 is used to connect a pressure sensor (not shown) by means of which the pressure prevailing in the combustion chamber 4 can be measured. From the terminal A11 also leads a line L11 axially through the connector body 2 into the combustion chamber 4. This line L11 serves to receive an ignition unit (not shown), with which the fuel mixture in the combustion chamber 4 can be ignited. Of the two powder connections A8, A9 each leads a line L8, L9 obliquely into the device. The two powder lines L8, L9 open substantially radially with respect to the longitudinal axis of the device in the pipe nozzle 5. The powder lines L8, L9 are used to supply coating powder, which upon entering the pipe nozzle 5 of entrained in the hot gas stream and at least partially melted by the prevailing temperature. Instead of supplying the coating material in powder form, this could for example also be supplied in wire form.

The Fig. 3 shows the device in a longitudinal section along the line BB in Fig. 1 , It can be seen in particular from this illustration that from the connection A5 a line L5 leads obliquely through the connection body 2 to a first (front) annular channel 14 of the nozzle body 7. From line A3, another line L3 leads obliquely through connection body 2 to the first ring channel 14 of nozzle body 7. While line L3 serves to optionally supply an oxidative gas such as oxygen, combustion chamber 4 can receive a second fuel via line L5 , preferably a fuel gas, are supplied. In any case, both fuel lines open into the common combustion chamber. 4

So that the supply of the fuel can be controlled via the fuel line L5, a flow regulator 28 is provided which serves both to open and close the associated fuel line L5 and to adjust the amount of fuel supplied per unit time. In order to control the supply of the oxidative gas in the line L3, a regulator 26 is provided. Possibly. it may be sufficient if the regulator 26 for the supply of oxidative gas is designed as an on-off switch. The supply of an oxidative gas via the line L3 is usually carried out only when the burner is operated with a fuel, namely when a first fuel, preferably kerosene, is supplied centrally via the line L1.

From the Fig. 4 which the device in a section along the line CC in Fig. 1 1, it can be seen that a line L2 leads from the connection A2 to a second (rear) annular channel 18 of the nozzle body 7. The line L2 serves to supply an oxidative gas, preferably oxygen into the combustion chamber. Thus, in addition to the two fuel lines and the line L2 lead to Supplying an oxidative gas in the common combustion chamber 4. In order to control the gas supply, a flow regulator 25 is provided.

The Fig. 5 shows the device in a longitudinal section along the line DD in Fig. 1 , It can be seen that the port A4 is connected via an oblique line with the front annular channel 14 of the nozzle body 7. The line L4 is preferably used to supply an inert gas, in particular nitrogen. In order to control the supply of the inert gas, a flow regulator 27 is provided.

In summary, it can thus be stated that the connections A3, A4 and A5 are connected via the three associated lines L3, L4 and L5 to the first annular channel 14 of the nozzle body 7, while the connection A2 leads via the line L2 to the second annular channel 18. If a medium is supplied via at least two of the three lines L3, L4, L5 connected to the front annular channel 14, then these media mix in the annular channel 14.

Based on Fig. 6a, 6b and 6c the structure of the nozzle body 7 is explained in more detail. The Fig. 6a shows the nozzle body 7 in a view from the combustion chamber side, while the Fig. 6b a longitudinal section through the nozzle body 7 along the line AA in Fig. 6a shows. The Fig. 6c shows a longitudinal section through the nozzle body 7 along the line BB in Fig. 6a ,

In the Fig. 6b It can be seen that from the second (rear) annular channel 18 axial holes 19 lead to the front end side of the nozzle body 7. These bores 19 form toward the combustion chamber side a first group of outlet openings 19A, via which the combustion chamber one medium or several media can / can be supplied.

In the Fig. 6c It can be seen that from the front annular channel 14 further axial bores 15 lead to the front end side of the nozzle body 7. The said bores 15 form towards the combustion chamber side a second group of outlet openings 15A.

In the Fig. 6a It can be seen that the group of bores 19 connected to the second (rear) annular channel 18 is arranged uniformly distributed on an inner circular line 20, while the further group of bores 15 connected to the first (front) annular channel 14 are evenly distributed on an outer circular line 16 is arranged. Both circular lines 16, 20 are arranged coaxially to a central outlet opening 13 of the nozzle body 7. The central opening 13 of the nozzle body 7 serves to receive an injection nozzle or an injection valve (not shown), which serves to inject the liquid fuel into the combustion chamber. The nozzle body 7 is provided for this purpose with an internal thread, which serves to fasten such an injection nozzle. Since such injectors are known, will not be discussed in detail here.

The basic advantages of such a device are that it can be used universally. Thus, the burner can for example be operated simultaneously with two fuels by the combustion chamber 4 via the nozzle body 7 - injector centrally a first fuel, such as kerosene, is supplied while the combustion chamber 4 at the same time another fuel, for example hydrogen, is supplied. The second fuel can be supplied via the bores 15, 19 of the outer or inner bolt circle of the nozzle body 7. In addition, the combustion chamber can be supplied according to requirements via the two ports A3, A4 any further media. Thus, via the port A2 and / or A3, an oxidative gas such as oxygen can be supplied. If the oxygen is supplied via the port A3, this mixes in the front annular channel 14 with the medium supplied via the port A4 and / or A5. For example, an inert gas such as nitrogen may also be supplied via port A4, causing the temperature in the combustion chamber to be lowered. In technical terms, this refers to the supply of a "cold" gas. The hole-circular arrangement of the holes 15, 19 and outlet openings 15A, 19A has the advantage that the various media of the combustion chamber can be supplied uniformly and centrally. Thus, the device is particularly suitable for melting coarse powders and application of thick layers and to produce rough surfaces, since during operation of the burner with two fuels per unit time very high temperatures and / or high melting rates of the coating powder and / or very high gas velocities can be achieved.

Of course, the burner can also be operated with only one fuel. Since both fuel lines are each provided with a flow regulator, a continuous or discontinuous transition from one to the other fuel is possible. Such a device makes it possible, for example, to apply a base coat with the one fuel, preferably kerosene, in order then to apply a top coat while supplying another fuel or both fuels. Until now, two different devices had to be used for such an operation.

Depending on the operating mode, it may be advantageous to let flow through the bores 15, 19 of the inner and / or outer pitch circle of the nozzle body 7, a gaseous medium into the combustion chamber, thus contamination of the holes and / or penetration of combustion chamber gases in said holes 15, 19 is prevented.

Depending on the desired operating mode, the nozzle body 7 serves to supply one or two fuels or fuel mixtures and one or more oxidative gases and any further gases.

Of course, the burner can also be operated only with a fuel, in principle, both liquid and gaseous fuels come into question. While kerosene is used in particular as the liquid fuel, as gaseous fuels, for example, hydrogen, natural gas, propylene, propane or ethylene can be used. It is understood that the aforementioned modes are by no means to be considered exhaustive, but that with the device defined in the claims a large number of different Operating modes is possible, of course, the number and arrangement of the connections and lines described can vary.

Another advantage of the inventively designed device or burner is that can be switched in operation without interruption of the one to the other fuel.

But the design of the actual burner can of course vary. Thus, the nozzle body 7 could be provided, for example, instead of or in addition to the holes arranged in a circular hole 15, 19 with an annular channel, or ring-shaped sections, via which one or more media of the combustion chamber 4 are supplied.

Claims (15)

A device for coating substrates by means of high-speed flame spraying, comprising a combustion chamber (4), a first fuel line (L1) for supplying a first liquid or gaseous fuel, a first gas line (L2) for supplying an oxidative gas and at least one further fuel line (L5) Supplying a further liquid or gaseous fuel, characterized in that both the first gas line (L2) and the two fuel lines (L1, L5) in a common combustion chamber (4) open, and that means (24, 28) are provided to to control the fuel supply in the two fuel lines (L1, L5) independently. Apparatus according to claim 1, characterized in that the one fuel line (L1) centrally via at least one outlet opening (13A) into the combustion chamber (4) opens, and that the further fuel line (L5) via a plurality of further outlet openings (15A) in the Combustion chamber (4) opens. Apparatus according to claim 1 or 2, characterized in that the one fuel line (L1) centrally via at least one outlet opening (13A) opens into the combustion chamber (4), and that the first gas line (L2) via a plurality of additional outlet openings (19A) in the combustion chamber (4) opens. Apparatus according to claim 2 or 3, characterized in that the outlet openings (15A) of the further fuel line (L5) on a circular line (16) are arranged, said outlet openings (15A) coaxial with the at least one centrally into the combustion chamber (4). opening outlet (13A) are arranged. Apparatus according to claim 3, characterized in that the outlet openings (19A) of the first gas line (L2) on a circular line (20) are arranged, which are arranged coaxially to the centrally opening into the combustion chamber (4) outlet opening (13A). Device according to claim 1, characterized in that the device has a nozzle body (7) adjoining the combustion chamber (4), which is exchangeably inserted into a connection body (2) of the device, wherein the nozzle body (7) is provided with a plurality of outlet openings ( 13A, 15A, 19A) and the two fuel lines (L1, L5) and the first gas line (L2) are connected to the nozzle body (7) in such a way that the combustion chamber (4) receives the media necessary for operating the device via the said Outlet openings (13A, 15A, 19A) of the nozzle body (7) can be fed. Apparatus according to claim 6, characterized in that the nozzle body (7) with a central outlet opening (13A) or nozzle is provided and further outlet openings (15A, 19A) distributed around the central outlet opening (13A) around, wherein the central outlet opening (13A) or nozzle is connected to the first fuel line (L1), and wherein said further exit openings (15A, 19A) are connected to at least one conduit (L3, L4) for supplying a further fuel and / or another gas. Apparatus according to claim 7, characterized in that the further outlet openings (15A, 19A) are arranged along two circular diameters (16, 20) provided with different diameters, wherein the outlet openings (15A) arranged along the outer circular line (16) are provided with a first , in the nozzle body (7) recessed annular channel (14) are connected, and wherein the along the inner circular line (20) arranged outlet openings (19A) with a second, in the nozzle body (7) embedded annular channel (18) are connected. Apparatus according to claim 8, characterized in that the first annular channel (14) with the further fuel line (L5) and / or another gas line (L3, L4) is connected. Apparatus according to claim 8 or 9, characterized in that the first annular channel (14) is connected to a further gas line (L4) for supplying an inert gas. Device according to one of claims 8 to 10, characterized in that the second annular channel (18) is connected to the first gas line (L2) for supplying an oxidative gas. Device according to one of the preceding claims, characterized in that means (25, 26, 27) are provided to control the gas supply at least in individual gas lines (L2, L3, L4). Device according to one of the preceding claims, characterized in that the device has a combustion chamber (4) limiting hollow body (3) which is interchangeable in a base body (1) of the device used, seen in the flow direction of the gases behind the hollow body (3 ) a pipe nozzle (5) is exchangeably inserted into the base body (1), and that the pipe nozzle (5) is provided with substantially radially or obliquely to the longitudinal axis extending Pulverzufuhröffungen. Apparatus according to claim 1, characterized in that the device comprises a nozzle body (7) adjoining the combustion chamber (4) for supplying the two fuels and the oxidative gas, the nozzle body (7) used interchangeably in a connection body (2) of the device is provided with a central outlet opening (13A) for the first fuel and two groups of further outlet openings (15A, 19A) for the further fuel and the oxidative gas, and wherein the one group of said further outlet openings (15A) on a outer circle (16) is arranged and the other group of said further outlet openings (19A) on an inner circular line (20) is arranged. Apparatus according to claim 14, characterized in that the two circular lines (16,20) are arranged coaxially to the central outlet opening (13A) and that the central outlet opening (13A) is connected to the first fuel line (L1) and the one group further outlet openings (19A) to the first gas line (L2) is connected, and that the other group of the further outlet openings (15A,) connected to the further fuel line (L5) and at least one further line (L3, L4) for supplying a further gas is.

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