NOZZLE CONSTRUCTION FOR THERMAL SPRAYING BY MEANS OF A SUSPENSION OR A PRECURSOR SOLUTION

Abstract

The invention relates to the nozzle construction for thermal spraying by means of a suspension, in which particles are contained, or a precursor solution, by means of which particles or precursor solution a layer is formed on a substrate, and which suspension or precursor solution is fed into a burner chamber or into a plasma torch, in which heating and acceleration of the particles is achieved, wherein a connection point for feeding the suspension or the precursor solution, a holder, and a nozzle insert are present. The nozzle insert has, with a tubular element arranged in the direction of the burner chamber or perpendicularly in HVOF flame or plasma torch and with an end face arranged opposite the burner chamber, a flange-shaped expanded section, which lies against a seat formed in the holder in the installed state. The contours of the flange-shaped expanded section and of the seat are complementary to each other such that the surfaces of the flange-shaped expanded section and of the seat are in direct contact with each other and an end stop and a seal are formed in this region.

Claims

1. A nozzle construction for thermal spraying using a suspension that contains particles or a precursor solution, with which a layer is formed on a substrate, and that is fed into a burner chamber or into a plasma torch in which the particles are heated and accelerated, wherein the nozzle construction is formed with a port (1) for a feed (4) for the suspension or the precursor solution, with a holder (2) and with a nozzle insert (3), and the nozzle insert (3) has a tubular element (3.1) arranged in the direction of the burner chamber or perpendicularly in an HVOF flame or plasma torch, and, on the end face arranged opposite the burner chamber, a flange-like widened portion (3.2), which, in the installed state, bears against a seat formed in the holder (2), and in this case the contours of the flange-like widened portion (3.2) and of the seat are formed in a complementary manner to one another such that the surfaces of the flange-like widened portion (3.2) and of the seat are in direct contact with one another, such that, in this region, an end stop and a seal are formed.

2. The nozzle construction as claimed in claim 1, characterized in that the flange-like widened portion (3.2) is formed from or with a polymer and the tubular element (3.1) from metal, preferably from passivated corrosion-resistant stainless steel.

3. The nozzle construction as claimed in claim 1, characterized in that the tubular element (3.1) and the flange-like widened portion (3.2) are connected together in a form-fitting, force-fitting and/or materially bonded manner.

4. The nozzle construction as claimed in claim 1, characterized in that there is a conical region on the flange-like widened portion (3.2).

5. The nozzle construction as claimed in claim 1, characterized in that the nozzle insert (3) is fastened interchangeably in the holder (2).

6. The nozzle construction as claimed in claim 1, characterized in that nozzle inserts (3) that have tubular elements (3.1) of different lengths and/or have different inside diameters are able to be fastened in the holder (2).

7. The nozzle construction as claimed in claim 1, characterized in that the tubular element (3.1) has a maximum inside diameter of 0.8 mm, preferably 0.25 mm.

8. The nozzle construction as claimed in claim 1, characterized in that the holder (2) is coolable.

Description

[0029] In the following text, the invention will be explained in more detail by way of an example.

[0030] In the drawing:

[0031] FIG. 1 shows a cross-sectional illustration through an example of a nozzle construction according to the invention.

[0032] In this case, a suspension feed 4, of which only a small part is indicated in FIG. 1, is fastened to a port 1. The port 1 can be a conventional connection with a union nut. The port 1 is present on a holder 2 that is hollow on the inside.

[0033] Following the separation of the connection between the port 1 and suspension feed 4, a nozzle insert 3 can be introduced from the side of the holder 2 that is open in the region of the port 1 and be introduced as far as a seat that is formed inside the holder 2.

[0034] The nozzle insert 3 is formed with a tubular element 3.1, on which a flange-like widened portion 3.2 is formed on the end face directed in the direction of the holder interior. The end face, directed in the direction of the outlet opening, of the flange-like widened portion 3.2 is formed in a conical manner. The seat in the holder 2 has a region formed in a conical manner in a correspondingly complementary fashion. At least there, the surfaces of the seat and of the flange-like widened portion bear directly against one another extensively. A region adjoining the latter in the direction of the port 1 can be formed as a hollow cylinder in the holder 2 and as an outer lateral surface of a cylinder at the flange-like widened portion 3.2 of the nozzle insert 3, and form a corresponding longitudinal guide for the nozzle insert 3 in the holder 2.

[0035] The tubular element 3.1 has in this example a length of 9 mm, an inside diameter of 0.25 mm and an outside diameter of 0.52 mm. It was obtained by a method of cutting to the desired length from a tubular semifinished product made of stainless steel.

[0036] At one of its end faces, the flange-like widened portion 3.2 was formed in a manner known per se by means of plastics injection-molding and in the process connected to the tubular element 3.1 there at least in a force-fitting and/or materially bonded manner. The flange-like widened portion 3.2 can be formed with virtually any desired polymer that is able to be processed by plastics injection-molding.

[0037] In the example shown in FIG. 1, an additional internally hollow sheathing 5, through which the tubular element 3.1 in the direction of a burner chamber (not illustrated) or in the direction of a substrate to be coated by means of thermal spraying, is present on the end face of the holder 2. The sheathing 5 can be a constituent part of the holder 2 or be fastened as a separate element to the holder 2, for example by means of a screw connection. The sheathing 5 can in particular fulfill a protective function for the tubular element 3.1.