Patent Publication Number: US-2022220861-A1

Title: Method of cleaning blade of rotary device

Description:
TECHNICAL FIELD 
     The present disclosure relates to a method of cleaning a blade of a rotary device. 
     BACKGROUND 
     Rotary devices, such as a compressor of a gas turbine, produce compressed air by compressing air from the atmosphere. Since the air in the atmosphere contains various dust particles, the dust is usually removed by an intake filter, but at least part of the dust that cannot be removed adheres to rotor and stator blades of the compressor. If dust adheres to the rotor and stator blades, the compressor efficiency of the compressor decreases, which may lead to a decrease in power generation efficiency. Therefore, it is important to clean blades of the compressor. Patent documents 1 and 2 describe cleaning by spraying a cleaning liquid to a rotating engine to cause it to suction. 
     CITATION LIST 
     Patent Literature 
     
         
         Patent Document 1: JP5184611B 
         Patent Document 2: JP6255073B 
       
    
     SUMMARY 
     Problems to be Solved 
     However, in cleaning the compressor of the gas turbine, the cleaning method by spraying a cleaning liquid from the intake side while the compressor is rotating, as described in Patent Documents 1 and 2, shows improved performance, but does not sufficiently remove dirt, and it is necessary to open the gas turbine for periodic inspection to wipe the blades. 
     In view of the above, an object of at least one embodiment of the present disclosure is to provide a method of cleaning a blade of a rotary device whereby it is possible to improve the workability. 
     Solution to the Problems 
     To achieve the above object, a method of cleaning a blade of a rotary device according to the present disclose comprises: a first application step of applying a water-soluble cleaning liquid containing a surfactant to the blade; a setting-aside step of setting the blade to which the cleaning liquid has been applied aside; a first wiping step of wiping the blade after the setting-aside step; a second application step of applying water or a dilute cleaning liquid having a lower concentration of the surfactant than that in the cleaning liquid applied in the first application step to the blade after the first wiping step; and a second wiping step of wiping the blade after the second application step. 
     Advantageous Effects 
     According to the method of cleaning a blade of a rotary device of the present disclosure, oil stain is removed by the first application step, the setting-aside step, and the first wiping step, and adhesion of dust due to oil stain is loosened, so that part of the dust is removed together with the oil stain in the first wiping step. However, if the dust is inorganic substances, which are more easily removed by a cleaning liquid with a higher moisture concentration, they may not be completely removed by the first application step and the first wiping step. In response to this, in the second application step, water or a dilute cleaning liquid having a lower concentration of the surfactant than that in the cleaning liquid applied in the first application step to the blade is used, which increases the concentration of dissolved dust and the adsorption to a rag, making it easier to wipe off the dust in the second wiping step. As a result, it is possible to improve the workability of cleaning the blade. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  is a partial enlarged cross-sectional view of a blade of a rotary device for showing an example of the dirty state of the blade. 
         FIG. 2  is a flowchart of a method of cleaning a blade of a rotary device according to the present disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     Hereinafter, the method of cleaning a blade of rotary machinery according to embodiments of the present disclosure will be described with reference to the drawings. The following embodiments are illustrative and not intended to limit the present disclosure, and various modifications are possible within the scope of technical ideas of the present disclosure. 
     &lt;Description of Dirty State of Blade&gt; 
     Rotary devices such as, but not limited to, a compressor of a gas turbine, a gas compressor, and a turbocharger, produce compressed air by compressing air from the atmosphere. Since the air in the atmosphere contains various dust particles, the dust is usually removed by an intake filter, but at least part of the dust that cannot be removed adheres to blades of their rotary member. As shown in  FIG. 1 , dust  101  adhering to a surface  100   a  of a blade  100  is often fixed to the surface  100   a  due to oil stain  102 . The method of cleaning a blade of a rotary device described below is particularly effective for cleaning a blade in this state, although not limited to cleaning a blade in this state. 
     &lt;Description of Method of Cleaning Blade of Rotary Device&gt; 
     The method of cleaning a blade of a rotary device will be described in conjunction with the case of cleaning rotor and stator blades disposed in a compressor of a gas turbine. As shown in  FIG. 2 , in step S 1 , cleaning preparation is performed for cleaning work of the rotor and stator blades. For example, in the case where the casing defining the compartment of the compressor is configured to be disassembled into two parts, an upper part and a lower part, the rotor disposed in the compartment can be revealed by removing the upper part from the lower part. This rotor is lifted and removed from the compartment, and then fixed with the rotor hanged at a position (height) that is easy for the operator to work with. The cleaning operator can access both the rotor blade disposed in the hanged rotor and the stator blade fixed in the casing. 
     Once the cleaning preparation is completed, a cleaning liquid is applied to the surfaces of the rotor blade and the stator blade by spraying the cleaning liquid to the rotor blade and the stator blade (step S 2 ). The application of the cleaning liquid is not limited to spraying, but may be performed in any way, such as wiping the surface of the blade with a rag containing the cleaning liquid. 
     The cleaning liquid preferably used in the present method is a water-soluble cleaning liquid containing a surfactant. Since blades of a compressor are often coated with a sermetel coating, which is mainly composed of aluminum, or partially with a thermal barrier coating, in order not to adversely affect them, the cleaning liquid is preferably neutral, i.e., the pH of the cleaning liquid is preferably 6 to 8. Examples of such a cleaning liquid include CLEANTHROUGH TW-100 (pH 6.7), KS-1000 (pH 8), KS-7405 (pH 6.4), LC-940 and MC-02 (pH 7) commercially available from Kao Corporation. For example, CLEANTHROUGH TW-100 contains alkyl polyglucosides and polyhydroxyalkyl ethers as surfactants. 
     After applying the cleaning liquid to the surface of the blade, the blade is set aside as it is (step S 3 ). The setting-aside time is not particularly limited as it depends on the dirty state of the blade, but may be any time in the range of 1 to 60 minutes, for example, 5 minutes. If an organic solvent is used as the cleaning liquid, it evaporates when left to stand, but if a water-soluble cleaning liquid containing a surfactant is used, it can be left to stand in this way. This setting aside increases the emulsifying and dispersing effects of the surfactant on oil stain, thus improving the removal rate of oil stain. 
     After setting aside for a certain time, the surface of the blade is wiped with a rag (step S 4 ). Since oil stain adhering to the blade is emulsified and dispersed by the surfactant in step S 3 , at least part of the oil stain is removed from the surface of the blade by wiping with a rag in step S 4 . The emulsification and dispersion of the oil stain loosen the adhesion of the dust to the surface of the blade due to the oil stain, so that at least part of the dust can also be removed from the surface of the blade when wiping with a rag. 
     Then, in step S 5 , it is visually checked whether the oil stain remains on the surface of the blade wiped with the rag. If the oil stain remains, the process returns to step S 2 , and steps S 2  to S 4  are repeated. If it is determined that the oil stain have been completely removed by visual check in step S 5 , a dilute cleaning liquid, for example, but not limited to, a 10-fold dilute cleaning liquid, having a lower concentration of the surfactant than that in the cleaning liquid used in step S 2  is sprayed on the surface of the blade wiped with the rag to apply the dilute cleaning liquid to the surfaces of the rotor blade and the stator blade (step S 6 ). The application of the dilute cleaning liquid is not limited to spraying, but may be performed in any way, such as wiping the surface of the blade with a rag containing the dilute cleaning liquid, as in step S 2 . The pH of the dilute cleaning liquid is preferably 6 to 8 for the same reason as the cleaning liquid. 
     Then, in step S 7 , the surface of the blade is wiped with a rag. In step S 7 , since no oil stain remains, the dust is removed from the blade surface by wiping with a rag, together with the dilute cleaning liquid applied to the blade surface. If the dust is inorganic substances, a high concentration of the surfactant in the cleaning liquid reduces the dissolution or adsorption on the rag, so that they may not be completely removed by steps S 2  to S 4 . In response to this, in step S 6 , the dilute cleaning liquid having a lower concentration of the surfactant than that in the cleaning liquid applied in step S 2  to the blade is used, which increases the concentration of dissolved dust, making it easier to wipe off the dust in step S 7 . 
     Then, in step S 8 , it is visually checked whether the dust remains on the surface of the blade wiped with the rag. If the dust remains, the process returns to step S 6 , and steps S 6  and S 7  are repeated. If it is determined that the dust has been completely removed by visual check in step S 8 , the cleaning work is completed. 
     Thus, the oil stain is removed by steps S 2  to S 4 , and adhesion of the dust due to the oil stain is loosened, so that part of the dust is removed together with the oil stain in step S 4 . In step S 6 , the dilute cleaning liquid having a lower concentration of the surfactant than that in the cleaning liquid applied in step S 2  to the blade is used, making it easier to wipe off the dust in step S 7 . As a result, it is possible to improve the workability of cleaning the blade. 
     In step S 6 , the dilute cleaning liquid is applied to the surface of the blade, but water may be applied instead. After the cleaning liquid is applied to the surface of the blade in step S 2 , the cleaning liquid is wiped off with a rag in step S 4 , but part of the surfactant in the cleaning liquid often remains adhering to the surface of the blade. When water is applied to the surface of the blade in this state, the surfactant adhering to the blade dissolves in the water to produce a dilute cleaning liquid, so that it is possible to make the state similar to the state where the dilute cleaning liquid is applied to the surface of the blade. 
     (1) A method of cleaning a blade of a rotary device according to an aspect includes: a first application step (step S 2 ) of applying a water-soluble cleaning liquid containing a surfactant to the blade; a setting-aside step (step S 3 ) of setting the blade to which the cleaning liquid has been applied aside; a first wiping step (step S 4 ) of wiping the blade after the setting-aside step; a second application step (step S 6 ) of applying water or a dilute cleaning liquid having a lower concentration of the surfactant than that in the cleaning liquid applied in the first application step to the blade after the first wiping step; and a second wiping step (step S 7 ) of wiping the blade after the second application step. 
     Generally, dust adhering to the blade is often fixed to the blade surface due to oil stain. Therefore, according to the method of cleaning a blade of a rotary device of the present disclosure, the oil stain is removed by the first application step, the setting-aside step, and the first wiping step, and adhesion of the dust is loosened, so that part of the dust is removed together with the oil stain in the first wiping step. In the second application step, water or a dilute cleaning liquid having a lower concentration of the surfactant than that in the cleaning liquid applied in the first application step to the blade is used, making it easier to wipe off the dust in the second wiping step. As a result, it is possible to improve the workability of cleaning the blade. 
     (2) A method of cleaning a blade of a rotary device according to another aspect is the method of cleaning a blade of a rotary device described in (1) includes a cleaning preparation step (step S 1 ) of removing a rotary member including the blade from the rotary device and hanging the rotary member before the first application step (step S 2 ). 
     This configuration allows the operator to clean the blade while the rotary member including the blade is hanged at a position (height) that is easy for the operator to work with, thus improving the workability of cleaning the blade. 
     (3) A method of cleaning a blade of a rotary device according to still another aspect is the method of cleaning a blade of a rotary device described in (1) or (2) in which the first application step (step S 2 ), the setting-aside step (step S 3 ), and the first wiping step (step S 4 ) are repeated at least once in this order after the first wiping step (step S 4 ). 
     With this configuration, since the removal of oil stain is repeated, the oil stain can be reliably removed. 
     (4) A method of cleaning a blade of a rotary device according to still another aspect is the method of cleaning a blade of a rotary device described in any one of (1) to (3) in which the second application step (step S 6 ) and the second wiping step (step S 7 ) are repeated at least once in this order after the second wiping step (step S 7 ). 
     With this configuration, since the removal of dust is repeated, the dust can be reliably removed. 
     (5) A method of cleaning a blade of a rotary device according to an aspect is the method of cleaning a blade of a rotary device described in any one of (1) to (4) in which a time of setting the blade aside in the setting-aside step (step S 3 ) is 1 to 60 minutes. 
     With this configuration, since the emulsifying and dispersing effects of the surfactant on oil stain is increased, the oil stain can be reliably removed. 
     (6) A method of cleaning a blade of a rotary device according to an aspect is the method of cleaning a blade of a rotary device described in any one of (1) to (5) in which pH of the cleaning liquid and the dilute cleaning liquid is 6 to 8. 
     With this configuration, the cleaning liquid can be used for the blade coated with a sermetel coating, which is mainly composed of aluminum, or a part with a thermal barrier coating. 
     (7) A method of cleaning a blade of a rotary device according to an aspect is the method of cleaning a blade of a rotary device described in any one of (1) to (6) in which the rotary device is a compressor of a gas turbine, a gas compressor, or a turbocharger. 
     With this configuration, it is possible to improve the workability of cleaning the blade of a compressor of a gas turbine, a gas compressor, or a turbocharger. 
     REFERENCE SIGNS LIST 
     
         
           100  Blade 
           100   a  Surface (of blade) 
           101  Dust 
           102  Oil stain