DE102022104455A1 - Turbine jet engine cleaning concentrate, cleaning solution and use thereof - Google Patents

Abstract

The present invention relates to a concentrate for the production of a cleaning solution for aircraft jet engines. The concentrate comprises an aqueous solution with the following ingredients: - approx. 16 to approx. 20% by weight of one or more glycol ethers, - approx. 8 to approx. 10% by weight of one or more fatty alcohol alkoxylates, - approx. 8 to approx. 10 % by weight of 2-propylheptanol ethyl ether, - about 4 to about 6% by weight of one or more alkyl glycosides, - about 0.5 to about 1.5% by weight of triethanolamine, - about 0.1 to about 0 .5% by weight of one or more polycarboxylates, and- about 0.1 to about 0.5% by weight of one or more corrosion inhibitors.

Description

The present invention relates to a concentrate for the production of a cleaning solution for aircraft jet engines.

The invention also relates to a cleaning solution for aircraft jet engines, which can be obtained by diluting the concentrate.

Furthermore, the invention relates to the use of the cleaning solution for cleaning the interior of a jet engine.

In commercial aviation, the majority of aircraft used today are powered by turbine jet engines, mostly in the form of turbofan engines or turbojets. During the operation of jet engines, various components of the engine become soiled, in particular inorganic and/or organic substances such as soot, salts and hydrocarbons are deposited on the blades of the turbine. With increasing operating time of the engine, these deposits can lead to loss of performance, damage and thus also to an impairment of the safety of flight operations. Regular cleaning of the jet engines is therefore essential.

In order to be able to carry out a correspondingly effective cleaning, it has hitherto been necessary in most cases to at least partially dismantle the jet engine. Because of the significant labor involved in disassembly and assembly, in addition to the actual cleaning of the engine, this results in economic losses due to the long downtime of the engine.

It is therefore extremely desirable to carry out the cleaning of turbine jet engines in the fully assembled state on the aircraft, for which correspondingly effective cleaning agents are required.

The present invention is therefore based on the object of proposing a cleaning solution and a concentrate for its production, which enables effective cleaning of turbine jet engines, in particular also in the assembled state.

• - ca. 16 bis ca. 20 Gew.% eines oder mehrerer Glycolether,
• - ca. 8 bis ca. 10 Gew.% eines oder mehrerer Fettalkoholalkoxylate,
• - ca. 8 bis ca. 10 Gew.% 2-Propylheptanolethylether,
• - ca. 4 bis ca. 6 Gew.% eines oder mehrerer Alkylglykoside,
• - ca. 0,5 bis ca. 1,5 Gew.% Triethanolamin,
• - ca. 0,1 bis ca. 0,5 Gew.% eines oder mehrerer Polycarboxylate, und
• - ca. 0,1 bis ca. 0,5 Gew.% eines oder mehrerer Korrosionsinhibitoren.

This object is achieved according to the invention by a concentrate which comprises an aqueous solution with the following ingredients:

• - about 16 to about 20% by weight of one or more glycol ethers,
• - about 8 to about 10% by weight of one or more fatty alcohol alkoxylates,
• - about 8 to about 10% by weight of 2-propylheptanol ethyl ether,
• - about 4 to about 6% by weight of one or more alkyl glycosides,
• - about 0.5 to about 1.5% by weight of triethanolamine,
• - from about 0.1 to about 0.5% by weight of one or more polycarboxylates, and
• - from about 0.1 to about 0.5% by weight of one or more corrosion inhibitors.

Surprisingly, it has been shown that a cleaning solution with the ingredients mentioned, which can be obtained by diluting the concentrate according to the invention with water, enables particularly effective cleaning of turbine jet engines, in particular with regard to the effective removal of deposits on the turbine blades. In order to achieve this good cleaning effect, it is sufficient here to introduce the cleaning solution into the installed jet engine, in particular to spray it, as will be explained in detail further below.

The concentrate according to the invention comprises one or more glycol ethers as the main ingredient. It is preferred if the concentrate contains about 9 to about 11% by weight of dipropylene glycol monomethyl ether and about 7 to about 9% by weight of diethylene glycol monobutyl ether as the glycol ether.

The concentrate according to the invention preferably contains about 8 to about 10% by weight of a C ₉ to C ₁₁ fatty alcohol ethoxylate as the fatty alcohol alkoxylate.

Advantageously, the concentrate can also contain about 0.1 to 0.5% by weight of another fatty alcohol alkoxylate as an additional ingredient, which acts as a defoamer.

The concentrate according to the invention contains about 4 to about 6% by weight of one or more alkyl glycosides, preferably about 4 to about 5% by weight of hexyl-D-glucoside. The concentrate preferably contains about 0.5 to about 1.0% by weight of pentyl-D-xyloside as a further alkyl glycoside.

The concentrate according to the invention also contains one or more corrosion inhibitors. The concentrate preferably contains a reaction product of maleic anhydride, 2-ethylhexylamine and triethanolamine as a corrosion inhibitor.

• - ca. 10 Gew.% Dipropylenglycolmonomethylether,
• - ca. 8 Gew.% Diethylenglycolmonobutylether,
• - ca. 9 Gew.% eines C₉- bis C₁₁-Fettalkoholethoxylats,
• - ca. 9 Gew.% 2-Propylheptanolethylether,
• - ca. 4,5 Gew.% Hexyl-D-Glucosid,
• - ca. 0,6 Gew.% Pentyl-D-Xylosid,
• - ca. 1 Gew.% Triethanolamin,
• - ca. 0,4 Gew.% eines oder mehrerer Polycarboxylate,
• - ca. 0,2 Gew.% eines als Entschäumer wirkenden Fettalkoholalkoxylats, und
• - ca. 0,2 Gew.% eines Korrosionsinhibitors, insbesondere eines Reaktionsprodukts von Maleinsäureanhydrid, 2-Ethylhexylamin und Triethanolamin.

According to a particularly advantageous embodiment of the invention, the concentrate comprises an aqueous solution with the following ingredients:

• - about 10% by weight of dipropylene glycol monomethyl ether,
• - about 8% by weight of diethylene glycol monobutyl ether,
• - about 9% by weight of a C ₉ to C ₁₁ fatty alcohol ethoxylate,
• - about 9% by weight of 2-propylheptanol ethyl ether,
• - about 4.5% by weight of hexyl-D-glucoside,
• - about 0.6% by weight of pentyl-D-xyloside,
• - about 1% by weight of triethanolamine,
• - about 0.4% by weight of one or more polycarboxylates,
• - about 0.2% by weight of a fatty alcohol alkoxylate acting as a defoamer, and
• - about 0.2% by weight of a corrosion inhibitor, in particular a reaction product of maleic anhydride, 2-ethylhexylamine and triethanolamine.

Ingredients other than those mentioned in the above description, which are dissolved in water, are not required for the good cleaning performance of a cleaning solution prepared from the concentrate according to the invention, but are also not ruled out in principle. According to an advantageous embodiment of the invention, in addition to the ingredients mentioned and water, the concentrate contains less than about 1% by weight of other ingredients, preferably less than about 0.5% by weight, more preferably less than about 0.1% by weight .%.

In a particularly advantageous embodiment of the invention, the concentrate contains no other components apart from the ingredients mentioned and water.

To produce a ready-to-use cleaning solution, the concentrate according to the invention is diluted with water. The provision in the form of a concentrate reduces transport and storage costs, since the dilution can be carried out directly on site.

The subject matter of the present invention is therefore also a cleaning solution for aircraft jet engines, which can be obtained by diluting the concentrate according to the invention with water in a ratio of approximately 5:95 to approximately 30:70. A ratio of about 10:90 to about 20:80 is particularly preferred, especially since the concentrate according to the invention shows a very good cleaning performance even in such a 10 to 20% dilution.

The invention also relates to the use of the cleaning solution according to the invention for the internal cleaning of a turbine jet engine, in particular a turbofan engine or a turbojet. As already stated, the cleaning solution according to the invention is preferably used when the jet engine is completely assembled, as a result of which its downtime can be significantly reduced.

Within the scope of the use according to the invention, the cleaning solution is preferably introduced into the jet engine from the inflow side of the compressor and sucked out of the jet engine on the outflow side of the turbine. Favorably, the cleaning solution can also be circulated ie the cleaning solution sucked off on the outflow side of the turbine is reintroduced into the jet engine from the inflow side of the compressor.

The cleaning solution is advantageously introduced into the jet engine by means of a spray lance, preferably at a pressure of 5 bar or less. Higher pressures are not necessary for the effectiveness of the cleaning solution according to the invention and should also be avoided in order to avoid any damage. In principle, a conventional high-pressure cleaner can also be used to introduce the cleaning solution into the jet engine, whereby cleaning that is gentle on the material and at the same time effective is also possible here, depending on the pressure setting and spray distance.

When the cleaning solution is sprayed into the jet engine, it is advantageously atomized and flows through the engine components, with the cleaning solution effectively coming into contact in particular with the blades of the turbine in order to remove deposits of salts, soot, etc. there.

The suction of the cleaning solution on the outflow side of the turbine is advantageously carried out by means of a hood that is placed on the outflow side of the jet engine.

It is particularly preferred if the cleaning solution is introduced into the jet engine at a temperature of approx. 40 to approx. 60°C. It has been found that the cleaning performance is particularly good in this temperature range.

For effective cleaning, the cleaning solution is preferably introduced into and aspirated from the jet engine over a period of about 5 to about 10 minutes, preferably in a circuit as described above. Thereafter, the jet engine is advantageously flushed with water for a comparable period of time.

These and other advantages of the invention are explained in more detail using the following examples.

examples

1. Production of a concentrate according to the invention and a cleaning solution according to the invention

Table 1 below shows the components used with the respective proportions by weight for a specific exemplary embodiment of a concentrate according to the invention. Table 1: Composition of a concentrate according to the invention wt% component 10.0 dipropylene glycol monomethyl ether 8.0 diethylene glycol monobutyl ether 9.0 C ₉ -C ₁₁ fatty alcohol ethoxylate 6.5 2-propylheptanol ethyl ether 10.0 Solution of 2-propylheptanol ethyl ether (25-30%) and hexyl-D-glucoside (40-50%) 1.0 Pentyl-D-xyloside (55-65% solution) 1.0 triethanolamine 0.8 polycarboxylate 0.2 Reaction product of maleic anhydride, 2-ethylhexylamine and triethanolamine (corrosion inhibitor) 0.2 Fatty alcohol alkoxylate (defoamer) 53.3 Water

All components were dissolved in the water to produce the concentrate. A clear solution was obtained.

To prepare cleaning solutions according to the invention for the experiments described below, the concentrate was diluted with water, as indicated in each case, in the ratio of 5:95, 10:90 or 20:80.

2. Cleaning performance tested in the Gardener test

For a quantitative comparison of the cleaning performance of different cleaning solutions in the Gardener test, test dirt with a defined composition is applied to a white-painted steel panel and then wiped off with the cleaning solution to be tested using a wipe test machine.

• ca. 88 Gew.% feinster Quarz
• ca. 9 Gew.% Kaolin
• ca. 1 Gew.% Flammruß
• ca. 2 Gew.% Paraffinöl

The test dirt used for this test has the following composition based on DIN ISO 11379-1-B.4:

• approx. 88% by weight finest quartz
• approx. 9% by weight kaolin
• approx. 1% by weight lamp black
• approx. 2% by weight paraffin oil

2 parts of this test protector were mixed with 3 parts motor oil (0W40) to obtain a consistency suitable for the wipe test experiments. This mixture was applied evenly to the white painted test panels using a paint roller.

The cleaning performance of the respective cleaning solution results from the spectroscopically determined degrees of whiteness of the uncontaminated panel (W0), the contaminated panel (W1) and the cleaned panel (W2) according to the following formula: $$\text{cleaning performance}=100\text{\%*}\left(\text{W}2-\text{W}1\right)/\left(\text{W}0-\text{W}1\right)$$

The cleaning performance of the cleaning solution according to Example 1 according to the invention in a dilution of 5%, 10% and 20% was compared with the cleaning performance of a commercially available cleaning solution for jet engines in the same dilutions. The comparison cleaner is the product "ZOK MX Gold Standard" from the manufacturer ZOK International Group Ltd. The results are shown in Table 2 below. Table 2: Cleaning performance in the Gardener test dilution ZOK MX Gold Standard cleaning solution according to the invention 5:95 53.14% 75.64% 10:90 73.93% 87.72% 20:80 83.23% 93.31%

The results show that the cleaning solution according to the invention is clearly superior to the comparison product, in all the dilutions examined. In particular, the cleaning solution according to the invention shows a better cleaning performance even in a 10% dilution than the comparison product in a 20% dilution, which is used as standard in practice.

The possibility of using significantly smaller amounts of the concentrate according to the invention with improved cleaning performance leads to cost savings and reduced environmental pollution compared to the comparison product.

3. Checking the cleaning performance based on the surface roughness

The deposits that occur on the turbine blades of jet engines during operation (in particular from salts, soot and/or hydrocarbons) lead to an increase in the surface roughness of the blade surfaces, as a result of which the performance of the engine can be impaired.

The determination of the surface roughness according to EN ISO 25178 or the comparison of the roughness before and after cleaning is therefore a very meaningful parameter for the effectiveness of cleaning solutions for jet engines.

In this regard, the cleaning performance of the cleaning solution according to the invention according to Example 1 and the comparison product “ZOK MX Gold Standard” were compared with one another by means of a dip test, in each case in a dilution of 20:80. For this purpose, original, dirty turbine blades were placed in the respective cleaning solution for 4 or 10 minutes and then rinsed with water. The test was carried out at different temperatures of the cleaning solutions (20, 30, 40, 50 and 80 °C).

The surface roughness of the turbine blades was measured before and after cleaning EN ISO 25178 determined as the roughness value S _a . As a result, the percentage reduction in the roughness value due to the cleaning (ΔS _a ) is given in Table 3 below. Table 3: Reduction in surface roughness (ΔS _a ) in the immersion test temperature cleaning duration ZOK MX Gold Standard cleaning solution according to the invention 20°C 4 min (trial 1) -4% -19% 20°C 4 min (attempt 2) -9% -5% 20°C 10 min (trial 1) -1% -26% 20°C 10 min (experiment 2) -3% -8th% 30℃ 4 min (trial 1) -8th% -8th% 30℃ 4 min (attempt 2) -7% -17% 30℃ 4 min (trial 3) -2% -15% 40℃ 4 mins -10% -16% 50℃ 4 mins -7% -12% 50℃ 10 mins -7% -13% 80℃ 4 mins -5% -17% 80℃ 10 mins -11% -14%

Despite the relatively high scattering of the individual results in the repeated tests, the trend clearly shows the higher effectiveness of the cleaning solution according to the invention compared to the comparison product in reducing the surface roughness of soiled turbine blades.

The reduction in surface roughness was also examined using a spray test. The soiled turbine blades were sprayed with the respective cleaning solution (20:80 dilution) at 20 °C or 40 °C with a pressure of 5 bar and then rinsed with water. ΔS _a was determined as in the immersion test. The results are shown in Table 4 below. Table 4: Reduction in surface roughness (ΔS _a ) in the spray test temperature ZOK MX Gold Standard cleaning solution according to the invention 20°C -14% -17% 40℃ -13% -20%

The significantly improved cleaning performance of the cleaning solution according to the invention compared to the comparison product is also evident here, in particular at an elevated temperature of 40.degree.

QUOTES INCLUDED IN DESCRIPTION

This list of documents cited by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Non-patent Literature Cited

• DIN EN ISO 25178 [0039, 0041]

Claims (17)

Concentrate for the production of a cleaning solution for aircraft turbine jet engines, the concentrate comprising an aqueous solution with the following ingredients: - about 16 to about 20% by weight of one or more glycol ethers, - about 8 to about 10% by weight of one or more fatty alcohol alkoxylates, - about 8 to about 10% by weight of 2-propylheptanol ethyl ether, - about 4 to about 6% by weight of one or more alkyl glycosides, - about 0.5 to about 1.5% by weight of triethanolamine, - from about 0.1 to about 0.5% by weight of one or more polycarboxylates, and - from about 0.1 to about 0.5% by weight of one or more corrosion inhibitors. concentrate after claim 1 wherein the concentrate contains, as the glycol ether, about 9 to about 11% by weight dipropylene glycol monomethyl ether and about 7 to about 9% by weight diethylene glycol monobutyl ether. concentrate after claim 1 or 2 , wherein the concentrate contains about 8 to about 10% by weight of a C ₉ to C ₁₁ fatty alcohol ethoxylate as the fatty alcohol alkoxylate. concentrate after claim 3 , wherein the concentrate contains about 0.1 to about 0.5% by weight of another fatty alcohol alkoxylate that acts as a defoamer. Concentrate according to one of the preceding claims, wherein the concentrate contains about 4 to about 5% by weight of hexyl-D-glucoside as the alkyl glycoside. concentrate after claim 5 , wherein the concentrate contains about 0.5 to about 1.0% by weight of pentyl-D-xyloside as an additional alkyl glycoside. A concentrate according to any one of the preceding claims wherein the concentrate contains as a corrosion inhibitor a reaction product of maleic anhydride, 2-ethylhexylamine and triethanolamine. Concentrate according to one of the preceding claims, wherein the concentrate comprises an aqueous solution with the following ingredients: - about 10% by weight dipropylene glycol monomethyl ether, - about 8% by weight diethylene glycol monobutyl ether, - about 9% by weight of a C ₉ - to C ₁₁ -fatty alcohol ethoxylate, - approx. 9% by weight 2-propylheptanol ethyl ether, - approx. 4.5% by weight hexyl-D-glucoside, - approx. 0.6% by weight pentyl-D-xyloside, - approx. 1% by weight % triethanolamine, - about 0.4% by weight of one or more polycarboxylates, - about 0.2% by weight of a fatty alcohol alkoxylate acting as a defoamer, and - about 0.2% by weight of a corrosion inhibitor, in particular a reaction product of maleic anhydride , 2-ethylhexylamine and triethanolamine. Concentrate according to one of the preceding claims, wherein the concentrate contains less than about 1% by weight of other components in addition to the ingredients mentioned and water, preferably less than about 0.5% by weight, more preferably less than about 0.1% wt%. concentrate after claim 9 , whereby the concentrate contains no other ingredients apart from the ingredients mentioned and water. Cleaning solution for aircraft turbine jet engines, obtainable by diluting the concentrate according to any one of the preceding claims with water in a ratio of from about 5:95 to about 30:70, preferably from about 10:90 to about 20:80. using a cleaning solution claim 11 for the internal cleaning of a turbine jet engine, in particular a turbofan engine or a turbojet. use after claim 12 , wherein the cleaning solution is introduced into the jet engine from the inflow side of the compressor and is sucked out of the jet engine on the outflow side of the turbine. use after Claim 13 , wherein the cleaning solution is introduced into the jet engine by means of a spray lance, preferably at a pressure of 5 bar or less. use after Claim 13 or 14 , wherein the cleaning solution is sucked off by means of a hood that is placed on the jet engine on the downstream side of the turbine. Use after one of Claims 13 until 15 , whereby the cleaning solution is introduced into the jet engine at a temperature of approx. 40 to approx. 60 °C. Use after one of Claims 13 until 16 , wherein the cleaning solution is introduced into the jet engine and sucked out of it over a period of about 5 to about 10 minutes.