Biotechnological Method of Cleaning Applicable to Engineering Components Technical Field of the Invention Referring to biotechnology, this invention deals with a micro- biological method of cleaning applicable to various engineering components (such as machine, tractor, vessel, or aircraft parts) for the purpose of keeping them free from contamination. It is especially usable for cleaning the parts containing inaccessible internal areas (e. g. aircraft and other engine parts, or parts with complex surfaces). Aircraft engines incorporating components difficult to be cleaned are hereinafter provided as an example.

Description of the Prior Art While in operation, aircraft engine (D-30 KU, NK-8 and others) components (such as fuel piping, combustion chambers, fuel jets, air- gas system inner walls, or blades) get covered with contamination (deposits) of various kinds. The products of oil, fuel and working liquid high-molecular transformation, carbon deposits, varnish deposits, resins, and depositions are the contamination required to be removed in particular.

The following eight methods of the engine components cleaning are known [1-3]:

1. Washing of parts and assembles using synthetic detergents, 2. Dry cleaning of carbon deposits, 3. Electrochemical cleaning, 4. Vibration grinding and vibration polishing, 5. Cutting with electro-corundum, 6. Cleaning with solvents (petrol, acetone), 7. Washing in washers (such as UPD-8), based on the use of detergents, distilled water and hot water vapour, and 8. Mechanical cleaning.

Of the methods listed above, 1 and 2 are the most frequent and close to the invention described herein as for their technical nature and the results attained. Using these methods, the parts covered with carbon deposits or other matters are placed in a"rough-washing vat" containing, for instant, MS-8 detergent or a blend consisting of "Progress"fluid, white spirit and phenolic hard-coal creoline (total 5%), and water (95%); then the parts are rinsed with hot water and flushed with running cold water. Clarification, neutralisation, removal of corrosion from the part surfaces, and drying follow. Anticorrosive treatment is carried out in potassium bichromate or sodium bichromate for 1-2 minutes. MS-8 blend consists of the following (in per cents): calcine soda (38), sodium silicate (29), trisodium phosphate (25), synthamide (5), and water (5); working temperature of solutions is 40-60 <BR> <BR> °C<BR> 0 C.

Cleaning is a labour-consuming process taking total 7-9 % of time consumption. Moreover, detergents, containing aggressive agents, require subsequent neutralisation and vats (clarifying tanks) of large volumes, which has adverse environmental impact. Working with detergents such as AFT-1 or EKM is seriously hazardous to personnel because of ethyl acetate and kerosene contained in these detergents and large, non-hermetic tanks of 300-500 litres volume where such cleaning is carried out.

Summarv of the Invention The purpose of this invention is to submit the method of cleaning applicable to various engineering components which would be more effective, less expensive, and environment-friendly. Providing a method allowing more objective evaluation of the level of parts cleanness than the current five-degree scale of visual examination is an additional purpose.

The nature of the invention being submitted consists in the micro-organisms, specifically fungi, capability of degrading contamination (carbon deposits) occurring on various engineering components (machine, aircraft engines or tractor parts) in the course of operation. Such deposits can be the products of hydrocarbon fuel high- molecular transformation (asphaltenes, carbens) [4]. Carbens, the deposits basic components, are the products of hydrogen carbons cyclic polymerisation (polyphenylenes, polyxylylenes). These compounds (carbenes and carboids) make 80-85 %, asphaltenes 4-7 %, resins 6-14 %, and ashes 1.5 %. Another contamination form resin deposits and settlements of the following complex composition (in per cents): oil (50- 85), fuel (1-7), hydroxy-acids (2-15), and some others. The above

stated compounds can be substrates for higher fungi characterised with high degradation activity in relation to these compounds, which makes the cleaning of aircraft parts possible. To these effects, the following order specimens are used: Eurotiales-Aspergillus and Penicillium, namely A. flavus BKM F-25, A. ochraceum BKM F-43, A. niger BKM F- 33, P. firniculosum BKM F-284, P. expansum BKM F-230, and P. citrinum BKM F-253.

Contaminated parts-such as cylinders, fuel injectors/jets, compressor blades, jet apparatus blades (stage I and 11)-either have sweet wort agar applied (surface cultivation) or are placed in the Blumenthal-Roseman medium (immersion cultivation) consisting of the following (in grams/litre): sucrose (30); KCI (0.5) ; KH2PO4 (10); MGS04- 7H2O (10); (NH4) 2SO4 (10); and microelements (in milligram/litre): FeS04 (0.01) and ZnS04 (0.05). Then the sweet wort agar or medium are inoculated with the above listed fungi using either single fungus strain or the mix of several ascomyceteous fungi strains. The parts are becoming covered with fungi within 18-20 hours at temperature 27-28 °C at surface cultivation; within 60-70 hours, air mycelium is produced on the entire agar layer and the destruction of deposits and the part cleaning is under way.

Ascomycateous fungi are known to be strong allergens [6] which means a certain risk for personnel at the surface cultivation of ascomyceteous fungi. Under the conditions in question, however, delay in the formation of conidiums occurred which might be explained by the spore generation inhibiting resulting from the presence of naphthalene derivatives (which are the deposit components).

Providing a method allowing more objective evaluation of the level of aircraft parts cleanness than the current five-degree scale of visual examination is an additional purpose of this invention. A scanned

microscope, such as JEOL JSM-T300, is used for this purpose, with no gold powder application required. The results that have been achieved show distinctly the difference in the level of aircraft part cleanness allowing to consider that the micro-biological method of cleaning provides improved cleaning without any corrosive action.

Examples of the Embodiment of the Invention The process of aircraft parts cleaning described hereinafter is given as an example of this specific method: Example 1.

An aircraft part to be cleaned (such as a blade) is placed into a vessel, for instant a desiccator, on a plate closing the vessel bottom. The aircraft part has sweet wort agar applied on its surface in a layer 2-3 mm thick, prepared on the basis of 7°B wort. Once hardened, the agar layer has a water suspension of A. flavus BKM F-25 spores applied. To this effect, surface mycelium is cultivated for 5-6 days at 27-28 °C on sweet wort agar cheeks and then, after the formation of conidium vehicles with conidiums, the latter are removed using wet method to avoid the conidium dispersing in the air, thus protecting personnel from allergic diseases. Upon seeding agar with the inoculate such obtained, a cup of water is placed on the desiccator bottom to create humid atmosphere. The desiccator with aircraft parts is kept at the temperature of 27-28 °C. After 20-24 hours, the agar layer surface becomes covered with air mycelium, and after 70-80 hours, initial stages of the deposits disappearance and the parts gradual cleaning may be observed. Full cleaning, proved by examining with a scanning microscope, is observed within 5-8 days.

Example 2.

As in example 1 but with A. niger BKM F-33 conidium applied for the purpose of agar inoculation. In this case, the agar medium an aircraft part becomes covered a bit later (within 25-28 hours) and the completion of the parts cleaning is observed within 7-9 days.

Example 3.

As in example 1 but with P. fuscum or P. funiculosum BKM F-284 applied for the purpose of sweet wort agar inoculation. In this case, the agar medium on aircraft part, becomes covered with surface mycelium within 26-28 hours and the completion of the parts cleaning is observed within 9-10 days.

Example 4.

As in example 1 but with using the agar medium on the basis of Blumemthall-Roseman medium, containing however 0.5-1.0 per cent of sucrose. In this case, agar becomes covered within 26-29 hours and the completion of the parts cleaning is observed within 8-9 days.

Example 5.

As in example 1 but with immersing aircraft parts into a liquid medium having two-day mycelium grown, that means that the cultivation of A. flavus BKM F-25 is carried out in the immersed cultivation with stirring in a magnetic stirrer at room temperature. Mycelium grows in the form of pellets of diameter varying from 1 to 5 mm. Covering of the detached deposit lumps with mycelium is observed, with deposits degrading and fungi hyphae penetrating into the deposit lumps. In this case, cleaning

of parts from aircraft deposits is incomplete and more time is required (up to 10-12 days).

Example 6.

As in Example 1 but with the mix of strains, such as A. flavus BKM F-25 and P. citrinum BKM F-253, used for the purpose of sweet wort agar inoculation. In this case, the agar medium becomes covered within 23- 26 hours and the completion of parts cleaning within 10-12 days is observed.

Example 7.

As in Example 2 but applicable to parts covered with varnish. In this case, parts become covered with mycelium within 29-32 hours and the completion of parts cleaning from varnish within 10-12 days is observed.

Industrial applicability In such a way, the method being submitted allows cleaning of parts from contamination (such as carbon deposits or varnish deposits) without using detergents containing surface-active agents, solvents or other toxic environmental pollutants. Besides that, the micro-biological method of cleaning is non-corrosive for the aircraft engine parts and non-hazardous for personnel. Economic analysis has shown that the method being submitted is cost effective, reducing the costs for the cleaning of components, those containing inaccessible internal areas in particular, 1.5-2 times. Another advantage of the method being

submitted is that, with no special clarifying tanks required, water demand is reduced; neither heating to 50-60 °C is required.

Referenced Literature: 1. Aksenov, A. F.: Aircraft Fuels, Lubricants and Special Liquids.

1965. Transport. 269 pp. (prototype).

2. Nekrasov, A. N.: Aircraft Hydraulic Systems. 1979.

Masinostroienie. 240 pp.

3. Cleaning of Fuel Piping and Combustion Chamber Jet Injectors Using Washing Liquids under Operation Conditions. N MT-0143-81 Methodology. 1992. Kazanski plant (prototype).

4. Panok, K. K., Sarantchuk, L. I.: Carbon Deposition and Thermal Stability of Aircraft Oils. 1946. Aeroflot Publishing House Editing. 146 PP.

5. II All-Union Conference on Biological Detriments: Lectures Synopsis. Biological Detriments, Part I. 1981. Gorki: Nauka. 135 pp.

6. Pasternak, N. I., Brysin, V. G.: Allergenicity of Mouldy Fungi.

1965. Tashkent: Medicina. 65 pp.