Method for cleaning and then coating parts having cavities

Abstract

The invention relates to a method for cleaning a part (1) consisting of a plurality of components (12, 13), wherein the components (12, 13) of the part (1) have cavities (19), wherein the entire part (1) is first provided with a covering which covers the surfaces (4, 7, 16) to be protected, the cavity (19) is then cleaned by a pickle, the cavity (19) is then filled with a coating material which is activated by the application of heat and leads to a coating of the surface within the cavity (19) and simultaneously leads to an at least partial evaporation or removal of the covering from the masked surfaces (4, 7, 16).

Description

[0001] METHOD FOR CLEANING AND SUBSEQUENT COATING OF COMPONENTS WITH CAVITIES

[0002] The invention relates to the cleaning of components comprising internal cavities which are to be cleaned internally and, if necessary, re-coated or re-coated internally.

[0003] For some gas turbine burner components, the aluminizing of an inner channel or channels must be renewed after a period of operation or applied for the first time if the burner is to be used for another service interval.

[0004] Such a burner is disclosed, for example, in WO 2023 / 025423 Al.

[0005] Alumina coating processes are known from EP 1, 510, 592 Bl.

[0006] Depending on the severity of the contamination after operation, the interior with damaged alumina or corrosion must also be cleaned beforehand. Pickling processes are used for this cleaning, which would, however, also attack the other surfaces of the component.

[0007] For more complex components, the component to be reworked is removed, reworked separately, and then reassembled into the component. This increases the repair time.

[0008] It is therefore an object of the invention to solve the above-mentioned problem.

[0009] The object is achieved by a method according to claim 1.

[0010] The subclaims list further advantageous measures, which can be combined in any desired manner to achieve further advantages. The figure shows a component to be cleaned.

[0011] The figure and the description represent only exemplary embodiments of the invention.

[0012] The figure schematically shows a component 1 - a burner of a gas turbine - which is made up of several components, such as, for example, an outer wall 11, a centrally arranged distributor chamber 13 and nozzles 12 in the radially formed intermediate space between the distributor chamber 13 and the outer wall 11. Only one nozzle 12 is shown here as an example.

[0013] Outer wall 11 and distribution chamber 13 thus form, for example, an annular channel.

[0014] The nozzles 12 are designed in particular like blades of turbine blades.

[0015] The nozzles 12 and the distribution chamber 13 have cavities 19 which are not shown in detail.

[0016] When the term cavity is used below, this also includes, if applicable, several supply lines in the distribution chamber 13 or in the nozzles 12.

[0017] From the distribution chamber 13, fuel is fed via a cavity 19 (line) into a cavity 19 of the nozzle(s) 12.

[0018] The fuel or the mixture of fuel and air flows into a burner chamber 22 , which is then ignited in the burner chamber 22 .

[0019] The fuel flows out of the nozzle 12 through at least one opening 24 from the cavity 19 (not shown in dashed lines here).

[0020] As a rule, the nozzle 12 has several openings.

[0021] The component 1 therefore has a plurality of surfaces, such as an outer surface 4 of the outer wall 11, a further inner surface 7 of the outer wall 11, a surface of the distribution chamber 13 and a surface 16 of the nozzle 12.

[0022] To protect component 1 during pickling, the surfaces of the component are largely or completely covered with a coating.

[0023] This is preferably done by brushing and by simply immersing the entire component 1 in a bath containing an adhesive mass, so that a masking is produced on the outer 4 and inner surfaces 7, 16 of the component 1.

[0024] This can in particular be a silicone mask.

[0025] Component 1 is not broken down into its components.

[0026] Due to their geometry, the cavities 19 are preferably not provided with the masking, which, however, does not represent an obstacle.

[0027] In the next step, the cavity 19, in particular that of the nozzle 12, is cleaned by supplying pickling agent directly into the cavity 19, which at least dissolves a possible masking in the cavity 19, but also achieves a desired cleaning of the cavity 19 or the cavities 19 treated in this way.

[0028] Thereafter, a coating material is introduced into the cleaned and preferably rinsed cavity 19, preferably as a slip, which leads to alitization and / or chromization within the cavity 19 through and after heating.

[0029] The coating material can also be introduced only locally into the cavity 19, e.g. only into the cavities of the nozzles 12.

[0030] For this purpose, preferably an aluminum metal, a chromium metal and corresponding alloys or corresponding precursors and, if necessary, an activator, for example a halide, are filled into the cavity 19.

[0031] The entire component 1 with the filled cavity(ies) 19 is then placed in a furnace or otherwise heated and kept there at a correspondingly high temperature in a reduced atmosphere so that diffusible chromium or aluminum or their alloys are deposited on the surface of the cavity 19.

[0032] At the same time, the masking or silicone also evaporates, so that the entire component 1 is ready for use again for the next service.

[0033] The advantage is that the components 12, 13 of the component 1, which have the cavity 19 or cavities 19, do not have to be disassembled separately.

Claims

Patent claims 1. A method for cleaning a component (1) comprising a plurality of components (11, 12, 13) which have surfaces (4, 7, 16), wherein at least one component (11, 12, 13) of the component (1) has one or more cavities (19), wherein the component (1) is first provided with a mask, without being disassembled, which mask covers at least the surfaces (4, 7, 16) to be protected, then the cavity (19) is cleaned by a pickling agent, then the cavity (19) is at least partially filled with a coating material which is activated by the application of heat and leads to a coating of the surface within the cavity (19) and, beforehand or simultaneously, leads to at least partial evaporation or removal of the mask from the masked surfaces (4, 7, 16).

2. Method according to claim 1, wherein the component (1) is a burner of a gas turbine.

3. A method according to claim 1 or 2, wherein the masking is formed by silicone.

4. Method according to one or more of claims 1, 2 or 3, in which an alitization of the cavity (19) is carried out.

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