A METHOD FOR CLEANING A TURBOFAN ENGINE AND APPARATUS FOR USE THEREOF

Abstract

A method and apparatus for cleaning a turbofan engine by use of dry ice pellets and a plurality of nozzles. The method comprises steps of setting up the emitting device, activating the turbofan engine, initiating the emitting device for cleaning the turbofan engine, halting the turbofan engine and repeating the steps for various settings and parameters. The apparatus comprises an emitting device, a plurality of nozzles, a conduit means, and a clamp.

Claims

1-28. (canceled)

29. A method for cleaning a turbofan engine (100), comprising the steps of: setting up at least an emitting device with at least a conduit for directing the flow of cleaning substances; activating the turbofan engine; initiating the emitting device for cleaning process of the turbofan engine; and halting the turbofan engine and the emitting device; the method is characterized by the step of connecting at least a nozzle (200,300) to the conduit for discharging the cleaning substances towards inner parts of the turbofan engine, in which the at least a nozzle comprises a detachable tip (301), connector plug (303) and a coupling means (305) for connection to the conduit and said at least a nozzle is configured for cleaning inner parts of the turbofan engine through at least a boroscope port of said turbofan engine by blasting the cleaning substances via said at least an emitting device.

30. The method of claim 29, wherein the inner parts of the turbofan engine comprise any one or a combination of low pressure compressor and high pressure compressor.

31. The method of claim 30, wherein the step of setting up at least an emitting device with at least a conduit further comprising the steps of: inserting dry ice into the emitting device; supporting the at least a nozzle by means of a clamp attached to the turbofan engine bracket; and inserting a first nozzle for discharging the cleaning substances through a variable bleed valve door of the high pressure compressor.

32. The method of claim 31, wherein the weight of dry ice inserted into the emitting device is in the range of 5 to 15 kg.

33. The method of claim 32, wherein the weight of dry ice inserted into the emitting device is preferably 10 kg.

34. The method of claim 29, wherein the turbofan engine (100) is activated at revolutions per minute, rpm, in the range of 10 to 20 rpm.

35. The method of claim 34, wherein the turbofan engine is activated at rpm of preferably 15 rpm.

36. The method of claim 29, wherein the emitting device is initiated for a period of time of 2 to 4 minutes for cleaning the turbofan engine.

37. The method of claim 36, wherein the emitting device is initiated for a period of time, preferably 3 minutes for cleaning the turbofan engine.

38. The method of claim 30, wherein the step of setting up at least an emitting device with at least a conduit further comprising the steps of: inserting dry ice into the emitting device; and inserting a second nozzle for discharging the cleaning substances through boroscope ports of the high pressure compressor.

39. The method of claim 38, wherein the weight of dry ice inserted into the emitting device is in the range of 3 to 7 kg.

40. The method of claim 39, wherein the weight of dry ice inserted into the emitting device is preferably 5 kg.

41. The method of claim 29, wherein the emitting device is initiated for a period of time of 1 to 3 minutes for cleaning the turbofan engine.

42. The method of claim 41, wherein the emitting device is initiated for a period of time, preferably 2 minutes for cleaning the turbofan engine.

43. An apparatus for cleaning a turbofan engine (100), comprising: at least an emitting device for providing cleaning substances; and at least a conduit for directing the flow of cleaning substances from the emitting device; wherein the conduit is connected to at least a nozzle (200, 300) for discharging the cleaning substances towards the inner parts of the turbofan engine, in which the at least a nozzle comprises a detachable tip (301), for connection to the conduit, capable of cleaning the inner parts of the turbofan engine, and said at least a nozzle is configured for cleaning inner parts of the turbofan engine through at least a boroscope port of said turbofan engine by blasting the cleaning substances via said at least an emitting device.

44. The apparatus of claim 43, wherein the inner parts of the turbofan engine comprise any one or a combination of low pressure compressor and high pressure compressor.

45. The apparatus of claim 44, wherein the detachable tip (301) is attached to a connector plug (303) and a coupling means (305) for connection to the conduit.

46. The apparatus of claim 45, wherein the connector plug (303) is adjustable for replacement of the detachable tip (301).

47. The apparatus of claim 43, wherein the at least a nozzle discharges cleaning substances to the high pressure compressor of the turbofan engine.

48. The apparatus of claim 43, wherein the at least a nozzle is a first nozzle (200) inserted through a variable bleed valve door for discharging the cleaning substances into the high pressure compressor.

49. The apparatus of claim 43, wherein the at least a nozzle is a second nozzle (300) inserted through the boroscope port for discharging the cleaning substances into the high pressure compressor.

50. The apparatus of claim 43, wherein the apparatus further comprises a clamp that is attached to the turbofan engine bracket for supporting the at least a nozzle.

51. The apparatus of claim 43, wherein the cleaning substances are dry ice.

52. The apparatus of claim 51, wherein the dry ice are in pellets form.

53. The apparatus of claim 52, wherein the dry ice pellets have dimensions of less than 3 mm.

54. The apparatus of claim 53, wherein the dry ice pellets have dimensions of less than 0.5 mm.

55. The apparatus of claim 43, wherein the emitting device further comprises a scrambler for slicing the dry ice into pellets form.

56. The apparatus of claim 43, wherein the emitting device is operated automatically through a remote control.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0020] FIG. 1 illustrates a turbofan engine showing the location of variable bleed valve (VBV) door according to the present invention.

[0021] FIG. 2 illustrates a variable bleed valve (VBV) nozzle for inserting into the variable bleed valve (VBV) door pathway according to the present invention.

[0022] FIG. 3 illustrates a British Standard Institution (BSI) nozzle for inserting into the borescope port high pressure compressor (HPC).

[0023] FIG. 4 illustrates a flowchart for a method for cleaning a turbofan engine according to the present invention.

[0024] FIG. 5 illustrates a flowchart for a method for setting up the emitting device with the conduit according to the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0025] The abovementioned and other features and objects of this invention will become more apparent and better understood by reference to the following detailed description. It should be understood that the detailed description made known below is not intended to be exhaustive or limit the invention to the precise form disclosed as the invention may assume various alternative forms. All the relevant modifications and alterations made to the present invention as covered in the detailed description should be construed to fall within the scope of the appended claims. Therefore, the configuration of the invention is not limited to the configuration mentioned in the following description.

[0026] The present invention relates to a method and apparatus for cleaning a turbofan engine (100), more preferably a turbofan engine of an aeroplane. Common examples of a turbofan engine (100) are CFM56-5B4/3, CFM56-5B4/P, CFM56-5B46/P, CFM56-5B6/3, CFM Leap-1a26, Rolls-Royce Trent 700 and Rolls-Royce Trent 772b. It should be understood by the skilled addressee that these are just examples of turbofan engines and the present invention should not be limited to the use of these turbofan engines. As earlier described, a turbofan engine (100) comprises a fan blade, a low pressure compressor, LPC, a high pressure compressor (HPC), a combustion chamber, a high pressure turbine and a low pressure turbine. The method and apparatus for cleaning a turbofan engine (100) of the present invention herein described is focused at the HPC section of the turbofan engine. The cleaning substances are discharged to the HPC of the turbofan engine by means of a nozzle (200, 300).

[0027] Referring to FIG. 1, the variable bleed valve (VBV) is located after the low pressure compressor and at the start of the high pressure compressor. There is a variable bleed valve (VBV) door (101) for inspection and maintenance purposes. The high pressure compressor section comprises a number of blades attached to a shaft. A borescope or similarly a boroscope is an optical device comprising rigid or flexible tube with an eyepiece on one end and is used for visual inspection work of the turbofan engine (100) where the area to be inspected is inaccessible by other means. The high pressure compressor (HPC) comprises a plurality of borescope ports wherein the borescope may be inserted for inspection. There are a number of borescope ports at the high pressure compressor (HPC) that has been categorized by stages, and the number varies depending on the engine models and their engine makers.

[0028] Referring now to FIGS. 2 and 3, illustrated are preferred embodiments of nozzles (200, 300) of the apparatus for cleaning a turbofan engine (100) according to the present invention. The present invention describes an apparatus for cleaning a turbofan engine comprising at least an emitting device for providing cleaning substances and at least a conduit for directing the flow of cleaning substances form the emitting device. It is noted that the conduit is connected to at least a nozzle (200, 300) for discharging the cleaning substances towards the turbofan engine (100), in which the nozzle (200, 300) comprises a detachable tip (301) attached to a connector plug and a coupling means for connection to the conduit. The nozzle (200, 300) is capable of cleaning the inner parts of the turbofan engine (100). The inner parts of the turbofan engine are referring to any one or a combination of low pressure compressor (LPC) and high pressure compressor (HPC).

[0029] The emitting device of the present invention is also known as a blasting device, whereby cleaning substance is inserted into and blasted by the emitting device for cleaning the turbofan engine. The cleaning substances are dry ice, more preferably dry ice in pellets form. The dry ice used for cleaning the turbofan engine have dimensions of less than 3 mm, more preferably dimensions of less than 0.5 mm. The emitting device comprises a scrambler for slicing dry ice. The scrambler is custom made based on the specification required for the cleaning of the turbofan engine. Smaller dimensions of dry ice gives improved cleaning properties. As the dry ice impacts the engine turbine blades, the dry ice removes the contaminations from the blades and sublimes, leaving behind no residue. The emitting device can be controlled and run remotely after the nozzles (200, 300) are set up at the correct locations. There is a setting on the remote control for which manual blast can be switched to automatic blasts.

[0030] As there are a few processes to be executed for the cleaning of the turbofan engine (100), there are two main types of nozzles (200, 300) that are being used throughout the cleaning processes, the first nozzle operated at the variable bleed valve (VBV) door (101) pathway, herein now referred to as variable bleed valve (VBV) nozzles (200) and the second nozzle operated at the borescope port high pressure compressor (HPC), herein now referred to as BSI nozzles (300). There is a conduit means connected to the emitting device and at the same time the variable bleed valve (VBV) nozzles (200) or the BSI nozzles (300) are connected to the conduit through the rear tip (209, 309) of the nozzle.

[0031] FIG. 2 illustrates the first nozzle (200) for discharging the cleaning substances that will be inserted through the variable bleed valve (VBV) door (101) of the high pressure compressor (HPC). In order for the variable bleed valve (VBV) nozzle (200) to be inserted through the variable bleed valve (VBV) door (101) for discharge of the cleaning substances, at least a clamp is used to hold and support the variable bleed valve (VBV) nozzle (200) to the turbofan engine (100) bracket. In one of the embodiment of the invention, the clamp acts as a lock to maintain the position of the nozzle. In addition, the variable bleed valve (VBV) nozzle (200) for discharging the dry ice further comprises a flexible rotatable solid conduit (207) enabling a multi-directional flow of the cleaning substance. Optionally, the conduit can be in a fixed design instead of being flexible depending on the model of the turbofan engine. When the turbofan engine (100) is initiated and the cleaning substance discharged, the air pressure will push the dry ice through the high pressure compressor (HPC) and cleans the blades through its paths.

[0032] FIG. 3 illustrates the second nozzle (300) for discharging the cleaning substances is inserted through the boroscope port of the high pressure compressor (HPC). In order to achieve better cleaning results, the BSI nozzles (300) are inserted through a number of borescope port high pressure compressor (HPC) and if required, the BSI nozzles (300) are inserted through all the borescope port of the HPC and the cleaning substance are blasted simultaneously. The BSI nozzles (300) comprises a rear tip (309), a coupling means (305), a one touch fitting, a connector plug (303) and an detachable tip (301). The connector plug (303) comprises a screw for adjusting and replacement of the tip (301). The rear tip (309) is for connection to the conduit means of the emitting device. It should be noted that the at least a nozzle (200, 300) has pre-determined indication showing the nozzle direction as well as labels to indicate the length. The BSI nozzle (300) is designed based on the diameter, thread size of the boroscope port and length of the blades of the turbofan engine.

[0033] Referring to FIG. 4, illustrated are steps (400) of cleaning a turbofan engine (100) according to the present invention. The method comprises the steps of setting up at least an emitting device with at least a conduit for directing the flow of cleaning substances, activating the turbofan engine (100), initiating the emitting device for cleaning process of the turbofan engine (100), and halting the turbofan engine (100) and the emitting device. The abovementioned steps are then repeated for various settings (460). The method is characterized by the step of connecting at least a nozzle (200, 300) to the conduit for cleaning the inner parts of the turbofan engine (100) by discharging cleaning substances towards the turbofan engine (100) in which the nozzle (200,300) comprises a detachable tip (301), a connector plug (303) and a coupling means (305) for connection to the conduit and said at least a nozzle (200, 300) is configured for cleaning inner parts of the turbofan engine (100). The at least a nozzle (200, 300) discharges cleaning substances to the HPC of the turbofan engine. The inner parts of the turbofan engine (100) comprise any one or a combination of low pressure compressor (LPC) and high pressure compressor (HPC).

[0034] FIG. 5 illustrated are steps (410) of setting up the emitting device with the conduit for cleaning of the turbofan engine (100) according to the present invention. There are two main procedures for the cleaning of the turbofan engine (100), one is the cleaning operation at the variable bleed valve (VBV) door (101) pathway (415) and the other is the cleaning operation at the boroscope ports at the high pressure compressor (HPC) (417). For the cleaning operation at the variable bleed valve (VBV) door (101) pathway, the steps begin with the setting up the emitting device and inserting dry ice into the emitting device. The emitting device, also known as a blasting machine, is connected to at least a conduit means and a first nozzle (200) is connected to the conduit means (412). The conduit means herein may be referred to as a dry ice (or more particularly a solid form of CO.sub.2) hose, whereas the nozzle may be referred to as variable bleed valve (VBV) nozzle (200) which is the first nozzle (200). The variable bleed valve (VBV) nozzle (200) is inserted into the variable bleed valve (VBV) door (101) of the high pressure compressor (HPC) of the turbofan engine before the cleaning process begins. Thereafter, a clamp attached to the turbofan engine (100) bracket beam is used to support the variable bleed valve (VBV) nozzle (200) in place, and inserting a first nozzle (200) for discharging the cleaning substances through the variable bleed valve (VBV) door (101) of the high pressure compressor (HPC). Dry ice is inserted or poured into the emitting device (411). The amount of dry ice inserted or poured into the emitting device is in the range of 5 to 15 kg in weight, more preferably 10 kg in weight. The turbofan engine (100) is then initiated at revolutions per minute, rpm, preferably in the range of 10 to 20 rpm, more preferably 15 rpm (420). The emitting device is then turned on for a few minutes (440), in the period of 2 to 4 minutes, preferably 3 minutes. As the emitting device is turned on, the dry ice will be sprayed onto the turbofan engine (100). The dry ice hits the engine turbine parts and blades and cleans the dirt and particles off from the blades, then sublimes without leaving behind residues. The emitting device is then turned off, turbofan engine (100) switched off (450), clamp dismantled and variable bleed valve (VBV) nozzle (200) removed from the conduit means.

[0035] The cleaning operation at the borescope port high pressure compressor (HPC) (417) is carried out after the cleaning operation at the variable bleed valve (VBV) pathway and involves using of different nozzles, herein referred to as BSI nozzles (300), for different borescope port high pressure compressor (HPC) stages. The dimensions and sizes of the BSI nozzles (300) varies depending on the model of the turbofan engine.

[0036] Upon commencement of the cleaning operation at the borescope port high pressure compressor (HPC), the second nozzle (300) or also known as the BSI nozzle (300) is connected to the conduit means (413, 416). A first BSI nozzle (300) is inserted into the stage 1 (STG1) boroscope port (417). The first BSI nozzle (300) is aligned to face a suction side of the blade of the high pressure compressor (HPC). Dry ice is inserted or poured into the emitting device (411) and the second nozzle (300) is inserted for discharging the cleaning substances through boroscope ports of the high pressure compressor (HPC). The emitting device is also commonly known as a hopper. The amount of dry ice inserted into the emitting device is in the range of 3 to 7 kg in weight, more preferably 5 kg in weight. The turbofan engine (100) is then initiated at revolutions per minute, rpm, preferably in the range of 10 to 20 rpm, more preferably 15 rpm (420). The emitting device is then turned on for a few minutes (440), in the period of 1 to 3 minutes, preferably 2 minutes. As the emitting device is turned on, the dry ice will be sprayed onto the turbofan engine (100), for cleaning the blades of the turbofan engine (100). The emitting device is then turned off, and the turbofan engine (100) is switched off (450). A second BSI nozzle (300) is then aligned to face subsequent blades of the high pressure compressor (HPC). The cleaning process is then repeated (460). To repeat the process for further cleaning, a third BSI nozzle is inserted into the stage 3 (STG3) boroscope port and a further BSI nozzle is inserted into a further stage of boroscope port. By implementing the repeating steps, each surface of the multi stages blades, vanes, and inner casing of the high pressure compressor (HPC) will be thoroughly cleaned.

[0037] The preferred embodiment of the present invention as described in the foregoing description is an apparatus for cleaning a turbofan engine (100) comprising at least an emitting device for providing cleaning substances, and at least a conduit for directing the flow of cleaning substances from the emitting device, characterized in that the conduit is connected to at least a nozzle (200, 300) for discharging the cleaning substances towards the inner parts of the turbofan engine (100), in which the nozzle (200, 300) comprises a detachable tip (301), for connection to the conduit, capable of cleaning the inner parts of the turbofan engine (100), and said at least a nozzle (200, 300) is configured for cleaning inner parts of the turbofan engine through at least a boroscope port of said turbofan engine (100) by blasting the cleaning substances via said at least an emitting device.

[0038] The inner parts of the turbofan engine refer to any one or a combination of low pressure compressor (LPC) and high pressure compressor (HPC). The detachable tip (301) of the nozzle (200, 300) is attached to a connector plug (303) and a coupling means (305) for connection to the conduit. The connector plug (303) is adjustable for replacement of the detachable tip (301), and said at least a nozzle (200, 300) discharges cleaning substances to the high pressure compressor (HPC) of the turbofan engine (100). Said at least a nozzle is a first nozzle (200) inserted through the variable bleed valve (VBV) door (101) for discharging the cleaning substances into the high pressure compressor (HPC).

[0039] Said at least a nozzle is a second nozzle (300) inserted through the boroscope port for discharging the cleaning substances into the high pressure compressor, (HPC). The apparatus further comprises a clamp that is attached to the turbofan engine (100) bracket for supporting the nozzle (200). The cleaning substances are dry ice in the form of pellets form. The dry ice pellets have dimensions of less than 0.5 mm or less than 3 mm. The emitting device further comprises a scrambler for slicing the dry ice into pellets form. The emitting device is operated automatically through a remote control.

[0040] The invention described herein is susceptible to variations, modifications and/or additions other than those specifically described and it is to be understood that the invention includes all such variations, modifications and/or additions which fall within the scope of the following claims.