The method of applying a coating on the blades of a thermal turbomachine

 

(57) Abstract:

The invention relates to the field of corrosion protection and can be used in gas turbine processes. The essence of the invention is the coating on the blades of a thermal turbomachine using a high-speed method, flame plating, in which a protective layer is deposited on the surface of the base material with a particle velocity of at least 300 m/s Then the blades are subjected to further processing, which, depending on the needs serves to reduce surface roughness and/or for the application of the top layer. 6 Il.

This invention relates to a method of coating on the blades according to the restrictive part of paragraph 1 of the claims.

For example, in an open gas-turbine process is absorbed by the compressor, the air also contains water vapor, and solid and gaseous impurities. The latter are negatively with erosion, contamination and corrosion. Located on the blades deposits are partially significant concentration affecting components, such as NaCl and KCl. Salt lead along with high temperature corrosion in blade lattice turbine Rial blades. At high air humidity in the inlet area of the compressor is water vapour, which leads to increased corrosion and destruction of the front rows of blades. To prevent this, the blades rotating heat engines repeatedly covered with a protective coating. It is used for steam and gas turbine blades and compressor blades. Thus, we are talking primarily about how to improve the corrosion resistance and oxidizing effects, as well as against erosion and abrasion (wear). If the scapula, despite surface treatment, still have the damage, the extent of which could reduce the operational reliability, the blade is removed, replace with new or restored and again mounted. These dismantling and installation associated with relatively high costs and time-consuming. Then the actual state of the blade lattice becomes visible only after a relatively long time, i.e., after pre-treatment, hence the solution can be completed with the restoration of the blades or not, or should have, taken only much later.

The disadvantages of this method are the large loss of time, the higher is Stanovlenie blades. Hence proceeded to find ways and means to get out of this predicament.

In this regard, the known method according to which a rotor with blades rises from the stator to recover in a separate installation. Be plated rotors with blades must be degreased, if necessary, previously deposited organic coatings must be completely removed. Then subject to coverage sections give a roughened by dry sandblasting with alumina, and the metal surface is activated. Areas to be coated shall be marked with appropriate materials. After that, apply basic layers, and they are in each case must be burned. This leads to a prolonged procedure: the sintering process or the process of scalding lasts for approximately 55 hours and should be conducted four times on average. This sintering process or being burned during the coating consists of a heat treatment at a temperature of 350oC with a holding time of about 10-12 hours. Along with this, to separate technological operations should provide for a very large installation with specific geometric design, sleh">

The objective of the invention is to resolve these difficulties. The basis of the invention described in the claims, based on the task at little cost of time and expense to offer a more rational method for repairing a blade. The invention is also increasing the service life of the coating by selecting the appropriate method and the protective layer.

Significant advantages of the invention should be seen in the fact that the rotor blades for the first recovery process should not be removed from the stator clearing or removal of the protective layer may be carried out before stopping the machine, i.e. the compressor, i.e., during the final phase of the work. Thereby is achieved a uniform supply of blades for processing, and achieved thus the effectiveness of this cleaning process, which provides the most complete removal of the existing protective layer makes it possible to take immediate decisions about the restoration of the blades. This decision can be made after stopping the machine and remove the upper part of the stator. If, after appropriate review of the condition of the blades, the decision about their recovery, it is sufficient for the process of recovery operations. This leads to low production costs (repair costs) that does not interfere with periodic carrying out this type of treatment. Thus, the increased reliability of the set.

Another important benefit should be seen in the fact that the application of high-speed flame way metallization pre-processed in the assembled condition, the blades receive the corresponding protective layer on the Si - and Al-based, locally and as needed, and this method of coating can be carried out without heat treatment for a longer time and without using special installations. This simplifies the whole process of coating, while the costs get about half lower than in the known method. In addition, the service life of this type of coating is much higher than that applied to it at the present time the so-called combined layers. As pre-treatment after deposition of the protective layer is of great importance for the life of the coating, as necessary can be selectively taken directly corrective.

Due to this, in the shortest time get when the blades are very high quality, which guarantees operational reliability over a long period of time.

Preferred and useful improvements relevant to the invention solving the problem described in the other claims.

Hereinafter the invention is explained in more detail using the drawings, which show examples of embodiment of the invention. Everything not needed for the immediate understanding of the invention, the elements are excluded. The direction of flow of different environments indicated by arrows. The same elements in different figures are provided with identical reference signs.

In Fig. 1 shows a turbine unit for pre-treatment; Fig. 2 is a view in Fig. 1 in the plane 11-11 of Fig. 3 stage cleaning or removing the protective layer in an oscillating erosion tub; Fig. 4 view of the rotor according to Fig. 3 along the plane IV-IV of Fig. 5 way final cleaning jet nozzles; Fig.6 floor of the blades using a high-speed method flame metallization.

In Fig. 1 shows schematically a gas turbine unit 11, consisting mainly of a compressor part 11a of the combustion chamber 11 and the tubular portion 11C. When isimo this is the first cleaning blade before stopping the machine, i.e. compressor. The cleaning blade coating is preferably in the erosive destruction through makestring granulate. Needless to say, cleaning uncoated blades may only be done with the help of water solvent such as trichloroethylene. Through a centrally-located trimstring nozzle 1 (see also Fig. 2), acting in the suction channel of the compressor, after a certain time cleaner (granulate marketready, aqueous solution, and so on) is sprayed into the air flow to the compressor. Uniform and intensive supply 12 on the blades of the compressor is effective cleanup process when uncovered shoulder blades or complete removal of the old protective layer with blades coated. The cleaning process is repeated several times depending on the needs. As marketready granules at temperatures of approximately 300oC burns, no problems associated with waste disposal. When applying the aqueous solution can also take into account this point of view.

As for the schema, multi-jet nozzle 1 consists of a ball valve 2 connected in the direction of flow of cleaning materials to the mixing chamber 3 and the employee downstream from the mixing chamber 3 includes a reservoir 4, in which tapasin, for example, granules, and with the help of filter and inlet valve to ensure that the mixing chamber 3 was provided with a homogeneous material. The necessary pressure in the tank 4 is set using vozduhoprovodyaschih pipeline 10, and the pressure reducing valve 8 and the main valve 9 in the pipe are the following assistive technology scheme. Through relevant events can also be handled blade grille turbine.

If necessary, the blades are cleaned or removal of the protective layer. This occurs, as shown in Fig. 3 and 4, using an oscillating erosion of the bath 14. For this purpose, the rotor 11a and 11C with petals rises of the stator and put on the stage 13A and 13B so that a certain part of the blade lattice is immersed in a bath 14. By the oscillation generator 15 separate erosion components of the bath 14 begin to fluctuate, resulting in removal of residual contamination or residues of the protective layer on the blades. Thereby fundamentally can be processed all kinds of rotor blades of the gas turbine installation.

Final cleaning according to Fig. 5 is carried out using a fraction promiscuos named means, which may consist of glass. A certain part of the blade lattice is covered with a special casing 16, while 19 suction spray means is cleaned by one or more jet nozzles 17.

Other processing steps may be provided depending on the needs:

the rough grinding anyway still available corrosion pit in the most loaded areas;

inspection of blades;

control the size of the blades in case the latter were subjected to grinding;

the roughened surface by sandblasting;

before coating, it is recommended to heat the blade approximately 30oWith, for example, by using emitter.

In Fig. 6 shows the holding of a high-speed process flame plating. For this purpose provides accessible side of the shell 16, which covers a number of prepared blades. Using a spray gun 20, a protective layer is applied on the blades, and at once is possible to carry out manually control the nozzle 20. Suction 19 removes excess medium spans geologicheskiy operations:

to reduce the roughness of the surface is applied a light sanding with emery paper and/or streams, such as glass beads;

to protect the base layer and to further reduce surface roughness can be applied the top coat of varnish using a gun-spray. This finish does not require high-temperature long-term annealing (furnace is not needed). At least for the first rows of the compressor, where the operation is dominated by lower temperature, applied two-component lacquer.

An example for such outer layer is polyuretanegluing varnish on a regular basis.

Regarding the quality of the protective layer should be said that the conventional coating compressors often have low erosion resistance. As such galvanic protective layers are valid only if they exist in the system metal-coating-electrolyte decreases the protective effect of locally eroded layer.

Applied here, the protective layer based on aluminum is an active corrosionresistant layer, the composition of which is preferably as follows:

1. The protective layer consists of 6-15 wt. Si, the rest mass. Al, 5-15 wt. Si, the remainder Cu, Mn, Mg, Ni.

The chemical structure of the above-mentioned protective layers, and the above-described method of application (high speed type flame metallization) determine insensitive to erosion layer anode cathodic protection", which actively protects against corrosion of the core material. The method of application, which is a high-energy way of coating, ensures well linked with the base metal erosion-resistant protective layers that without a new specific protective layer further processing have the desired electrical connection with the main material.

Proposed protective layers may optionally be provided in the upper layer. This protective top layer can be, for example, black. Such protective top layer makes it easier to distinguish the icing on the blades with ice detectors. High-speed flame way metallization at the speed of particles of at least 300 m/s, gives an optimum connection of the cover with the main material of blades. Even with a thicker protective layers is guaranteed that the floor will not fall behind. This can be explained by the fact that at impact the NGOs first deposited layer. Maximum resistance to erosion can be explained by the fact that the applied layers have a very high hardness. Due to the proposed method turns out that the content of the oxide layer deeper than those sprayed in the air protective layers. This means that the layer is cleaner, making it not so rapidly oxidized, and the oxidation occurs, in any case, only on the surface. Due to the fact that the protective layers are very dense, porosity below 0.5% Destruction by corrosion is practically eliminated. When tested in salt spray to DIN 50021 standard ceramic aluminum layer was compared with the protective layer and the above-mentioned method. The results fully confirmed the above statements. To test the fatigue was conducted the same comparison: it was found that the load until the first of fatigue cracks in the blade coated with the above composition and the above-mentioned method is 20% higher than comparable blades. This means that the reliability of the blades against fatigue failure may be increased.

The above-described advantages, as well as the results after several thousand hours of operation of the compressor in the installation, close to the sea, has led to the increase of service life ulozhenie in the rotor or the stator, including preparing the surface of the blades after the opening of the turbomachine, and a protective layer, characterized in that before the opening of the turbomachine in its operating condition are cleaned using the supplied air flow, and after the preparation is applied a protective layer flame plated with a deposition rate of at least 300 l/s

2. The method according to p. 1, characterized in that as a means of supplied air flow, use organic abrasive material.

3. The method according to p. 1, characterized in that as a means of supplied air flow, using an aqueous solution of trichloroethylene.

4. The method according to p. 1, characterized in that the surface preparation result in vibration of the tub.

5. The method according to p. 1, characterized in that the flame metallization is applied protective of their composition, wt.

Si 6 15

Al the Rest

6. The method according to p. 1, characterized in that the flame metallization is applied a protective layer of aluminum.

7. The method according to p. 1, characterized in that the flame metallization is applied to the protective layer composition, wt.

Al 80

Si 5 15

Si and/or Mn and/or Mo and/or Ni and the Rest

8. The method according to p. 1, P> 9. The method according to PP.1 and 8, characterized in that after machining put a layer of polyurethane varnish on a synthetic basis.

 

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