Description:A METHOD AND SYSTEM OF INSPECTION OF LOW-PRESSURE STEAM TURBINE BLADE USING VIBRO-THERMOGRAPHY FOR DEFECTS
FIELD OF INVENTION
[0001] The present disclosure relates to a system and process of mixing gases for the nondestructive testing . More particularly, the invention relates to a system and method for Non-destructive evaluation (NDE) techniques for testing and defect detection of mechanical components, particularly focusing on Low Pressure (LP) turbine blades used in steam turbines
BACKGROUND OF THE INVENTION
[0002] Background description includes information that may be useful in understanding the present invention. It is not an admission that any of the information provided herein is prior art or relevant to the presently claimed invention, or that any publication specifically or implicitly referenced is prior art.
[0003] Traditionally, the inspection and evaluation of LP turbine blades have relied on methods that can be intrusive, time-consuming, and sometimes destructive. These methods often involve disassembly of the turbine components, leading to downtime and potential risks to the overall system integrity. Moreover, conventional testing techniques may not always effectively detect hidden defects or early signs of degradation, potentially leading to unexpected failures and costly downtime.
[0004] Traditional methods for inspecting LP turbine blades often involve the disassembly of turbine components, which can disrupt operations and pose risks to system integrity. Disassembly requires shutting down the turbine and dismantling parts, leading to extended downtime for maintenance activities. This intrusiveness not only increases the time and labor required for inspections but also introduces the potential for errors or damage during the reassembly process.
[0005] Visual inspection, dye penetrant testing, and magnetic particle inspection, commonly used in traditional methods, are primarily surface-based techniques. While effective for detecting surface defects, these methods may fail to identify subsurface defects or early-stage degradation within LP turbine blades. This limitation can result in undetected flaws that could lead to unexpected failures or reduced performance over time, posing safety risks and increasing maintenance costs.
[0006] The inspection methods are often time-consuming due to the need for disassembly, inspection, and reassembly of turbine components. This process can significantly prolong downtime, impacting operational efficiency and revenue generation. Moreover, the time required for manual inspection and interpretation of results further adds to the overall duration of maintenance activities, delaying the return to normal operations.
[0007] Certain traditional testing techniques, such as radiographic testing, involve the use of radiation to penetrate the material being inspected. While effective for detecting internal defects, this method can be destructive and may cause damage to the turbine blade material over time. Additionally, the handling and disposal of radioactive materials pose environmental and safety concerns, further complicating the inspection process.
[0008] The methods often rely heavily on manual labor for setup, execution, and interpretation of results. Skilled technicians are required to perform visual inspections, apply dye penetrant, or interpret magnetic particle indications, adding to the overall cost and complexity of the inspection process. Moreover, the reliance on human judgment increases the risk of errors or inconsistencies in inspection results.
[0009] The radiographic testing, involve the use of radioactive materials, which can pose environmental hazards if not handled properly. The disposal of radioactive waste and the potential for radiation exposure during testing raise concerns about environmental sustainability and worker safety. As regulatory standards become more stringent, addressing these environmental impacts becomes increasingly important in the selection of inspection methods.
[0010] The method can incur significant costs associated with equipment, labor, and downtime. The need for specialized tools and trained personnel, along with the prolonged downtime for turbine maintenance, contributes to higher overall expenses. Additionally, the potential for missed defects or undetected issues may result in additional costs for unplanned repairs or premature component replacement, further impacting the economic viability of traditional inspection approaches.
[0011] The contemporary prior art faces several challenges that necessitate the development of the present invention. Traditional LP turbine blade inspection methods involve intrusive disassembly, limited detection capabilities, time-consuming processes, potential destructiveness due to radiation, labor-intensive procedures, environmental concerns, and high costs. These challenges collectively hinder the efficiency and reliability. Thus there is a pressing need to achieve the same.
OBJECTS OF THE INVENTION
[0012] Some of the objects of the present disclosure, which at least one embodiment herein satisfy, are listed herein below.
[0013] It is an object of the present subject matter to provide title, which overcomes the aforementioned and other drawbacks existing in the prior art fixture and methods.
[0014] It is a principal object of the present subject matter to introduce a system and method of non-destructive evaluation method for LP turbine blades using vibro-thermography.
[0015] It is another significant object of the present subject matter to propose the system and method to mminimize downtime and ensure operational safety.
[0016] It is another significant object of the present subject matter to propose the system and method to streamline the inspection process and reduce reliance on manual labour.
[0017] It is another significant object of the present subject matter to propose the system and method to enhance defect detection sensitivity and improve overall cost-effectiveness.
[0018] These and other objects and advantages of the present subject matter will be apparent to a person skilled in the art after consideration of the following detailed description taking into consideration with accompanied drawings in which preferred embodiments of the present subject matter are illustrated.
SUMMARY OF THE INVENTION
[0019] This summary is provided to introduce the concept of a method and a system of inspection of low-pressure steam turbine blade using vibro-thermography for defects. The concepts are further described below in the detailed description. This summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used to limit the scope of the claimed subject matter.
[0020] The invention relates to a method and a system of inspection of low-pressure steam turbine blade using vibro-thermography for defects. The method comprises of mounting a Low Pressure (LP) turbine blade for testing and defect detection, applying pressure to a LP turbine blade using a pneumatic cylinder mounted on a cross beam to ensure secure fixation during testing, introducing ultrasound energy into a blade root for excitation to facilitate defect detection, capturing thermal images of the LP turbine blade during ultrasound excitation to monitor temperature variations and processing the captured thermal images to form a defect signal indicative of structural anomalies within the LP turbine blade.
[0021] To further understand the characteristics and technical contents of the present subject matter, a description relating thereto will be made with reference to the accompanying drawings. However, the drawings are illustrative only but not used to limit the scope of the present subject matter.
[0022] Various objects, features, aspects, and advantages of the inventive subject matter will become more apparent from the following detailed description of preferred embodiments, along with the accompanying drawing figures in which like numerals represent like components.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS
[0023] It is to be noted, however, that the appended drawings illustrate only typical embodiments of the present subject matter and are therefore not to be considered for limiting of its scope, for the invention may admit to other equally effective embodiments. The detailed description is described with reference to the accompanying figures. In the figures, a reference number identifies the figure in which the reference number first appears. The same numbers are used throughout the figures to reference like features and components. Some embodiments of improved fixture or methods or structure in accordance with embodiments of the present subject matter are now described, by way of example, and with reference to the accompanying figures, in which
[0024] Fig. 1 illustrates a flow chart of a method of inspection of low-pressure steam turbine blade using vibro-thermography for defects in accordance with an embodiment of the present disclosure;
[0025] Fig. 2 illustrates a test setup of a system of inspection of low-pressure steam turbine blade using vibro-thermography for defects in accordance with an embodiment of the present disclosure; and
[0026] Fig. 3 illustrates a test results of Defect signals of low-pressure steam turbine blade using vibro-thermography for defects in accordance with an embodiment of the present disclosure.
[0027] The figures depict embodiments of the present subject matter for the purposes of illustration only. A person skilled in the art will easily recognize from the following description that alternative embodiments of the structures and methods illustrated herein may be employed without departing from the principles of the disclosure described herein.

DETAILED DESCRIPTION OF THE INVENTION WITH REFERENCE TO THE ACCOMPANYING DRAWINGS
[0028] A few aspects of the present disclosure are explained in detail below with reference to the various figures. Example implementations are described to illustrate the disclosed subject matter, not to limit its scope, which is defined by the claims. Those of ordinary skill in the art will recognize a number of equivalent variations of the various features provided in the description that follows.
[0029] As used in the description herein and throughout the claims that follow, the meaning of “a,” “an,” and “the” includes plural reference unless the context clearly dictates otherwise. Also, as used in the description herein, the meaning of “in” includes “in” and “on” unless the context clearly dictates otherwise.
[0030] Each of the appended claims defines a separate invention, which for infringement purposes is recognized as including equivalents to the various elements or limitations specified in the claims. Depending on the context, all references below to the "invention" may in some cases refer to certain specific embodiments only. In other cases, it will be recognized that references to the “invention" will refer to subject matter recited in one or more, but not necessarily all, of the claims.
[0031] Groupings of alternative elements or embodiments of the invention disclosed herein are not to be construed as limitations. Each group member can be referred to and claimed individually or in any combination with other members of the group or other elements found herein. One or more members of a group can be included in, or deleted from, a group for reasons of convenience and/or patentability. When any such inclusion or deletion occurs, the specification is herein deemed to contain the group as modified thus fulfilling the written description of all groups used in the appended claims.
[0032] Various embodiments are further described herein with reference to the accompanying figures. It should be noted that the description and figures relate to exemplary embodiments and should not be construed as a limitation to the subject matter of the present disclosure. It is also to be understood that various arrangements may be devised that, although not explicitly described or shown herein, embody the principles of the subject matter of the present disclosure. Moreover, all statements herein reciting principles, aspects, and embodiments of the subject matter of the present disclosure, as well as specific examples, are intended to encompass equivalents thereof. Yet further, for the sake of brevity, operation or working principles pertaining to the technical material that is known in the technical field of the present disclosure have not been described in detail so as not to unnecessarily obscure the present disclosure.
[0033] Fig. 1 illustrates a flow chart of a method of inspection of low-pressure steam turbine blade using vibro-thermography for defects in accordance with an embodiment of the present disclosure. The method(100) of inspection of low-pressure steam turbine blade using vibro-thermography for defects (100) comprises of mounting(102), a Low Pressure (LP) turbine blade for testing and defect detection, applying(104), a predetermined pressure to a LP turbine blade using a pneumatic cylinder mounted on a cross beam to ensure secure fixation during testing, introducing(106), a ultrasound energy into a blade root for excitation to facilitate defect detection, capturing(108), the thermal images of the LP turbine blade during ultrasound excitation to monitor temperature variations and processing(110), the captured thermal images to form a defect signal indicative of structural anomalies within the LP turbine blade.
[0034] At step 102, mounting a Low Pressure (LP) turbine blade for testing and defect detection involves securing the LP turbine blade in a fixture to ensure stability during inspection. Proper mounting is crucial to prevent movement or vibration that could affect the accuracy of the inspection process.
[0035] At step 104, applying pressure to a LP turbine blade using a pneumatic cylinder mounted on a cross beam to ensure secure fixation during testing is performed. The pneumatic cylinder applies pressure to the LP turbine blade, ensuring it remains securely fixed in place during the inspection. This pressure helps to maintain consistent contact between the blade and the inspection equipment, reducing the risk of measurement errors.
[0036] At step 106, ultrasound energy is applied to the blade root using a specialized transducer. This energy induces controlled vibrations within the blade, which can reveal defects or anomalies that may be present. The excitation process helps to highlight areas of structural weakness or damage within the LP turbine blade.
[0037] At step 108, capturing thermal images of the LP turbine blade during ultrasound excitation to monitor temperature variations is performed. Thermal imaging cameras are used to capture images of the LP turbine blade as it undergoes ultrasound excitation. These images provide valuable information about temperature variations across the surface of the blade, which can indicate the presence of defects or abnormalities.
[0038] At step 110, the captured thermal images are processed using image processing algorithms to analyse temperature variations and identify potential defects within the LP turbine blade. By correlating temperature data with the location and intensity of ultrasound excitation, a defect signal is generated, indicating areas of concern that may require further investigation or maintenance.
[0039] Fig. 2 illustrates a test setup of a system of inspection of low-pressure steam turbine blade using vibro-thermography for defects in accordance with an embodiment of the present disclosure. The system for inspection of low-pressure steam turbine blade using vibro-thermography for defects comprises of a fixture with a wooden base for securing the LP turbine blade, ensuring stability during evaluation, a pneumatic cylinder housing an ultrasonic transducer mounted on a cross beam for applying pressure to secure the LP turbine blade during testing, an ultrasound excitation system configured to introduce ultrasound energy into the blade root for controlled excitation, a thermal imaging camera positioned to capture thermal images of the LP turbine blade during ultrasound excitation and a processing unit for analyzing the captured thermal images to form a defect signal indicative of structural anomalies within the LP turbine blade.
[0040] The fixture with wooden base serves as the foundation for securing the LP turbine blade during evaluation. The fixture is designed with a wooden base to ensure stability, minimizing any movement or vibrations that could affect the accuracy of the inspection process. It provides a reliable platform for mounting the turbine blade securely.
[0041] The pneumatic piston is equipped with an ultrasonic transducer, which is responsible for establishing contact with the LP turbine blade root. By applying downward movement, the piston ensures sufficient contact pressure between the transducer and the blade, facilitating the transmission of ultrasonic energy into the material. This component plays a crucial role in enabling the ultrasonic excitation of the turbine blade.
[0042] The ultrasonic excitation system is designed to apply sound energy with specific parameters to the LP turbine blade. It operates within a frequency range of 15-25 kHz and has a maximum power output of 2.2 kW. By generating ultrasonic waves in a predetermined waveform, the excitation system induces controlled vibrations within the turbine blade, which can reveal defects or anomalies present in the material.
[0043] The thermal imaging camera is positioned on both sides of the LP turbine blade, thermal imaging cameras are used to capture thermal images during the ultrasonic excitation process. These cameras detect and record variations in temperature across the surface of the blade, providing valuable insights into the thermal response of the material to the applied ultrasound energy. The captured thermal images serve as essential data for defect detection and analysis.
[0044] The processing unit is responsible for processing the captured thermal images to identify defects within the LP turbine blade. Utilizing advanced image processing algorithms, the analysis system analyzes temperature variations and patterns across the blade surface, identifying any abnormalities indicative of structural defects. It plays a crucial role in evaluating the structural integrity of the turbine blade and determining the presence of any potential issues requiring further attention.
ADVANTAGES OF THE INVENTION

[0045] The proposed system and method have the following advantages over the contemporary prior arts:
• Non-intrusive Inspection: Unlike traditional methods that require intrusive disassembly, the invention offers a non-destructive means of inspecting LP turbine blades. This minimizes downtime and reduces the risk of damaging the components during inspection.
• Enhanced Detection Capabilities: The invention addresses the limited detection capabilities of traditional methods by integrating advanced technologies such as vibro-thermography. This enables more comprehensive defect detection, including hidden flaws or early signs of degradation.
• Time Efficiency: By streamlining the inspection process and eliminating the need for extensive disassembly, the invention saves time. This contributes to increased operational efficiency and reduces the impact on overall turbine maintenance schedules.
• Safety Considerations: The non-destructive nature of the inspection method eliminates potential hazards associated with radiation exposure, mitigating safety risks for personnel involved in the inspection process.
• Cost-effectiveness: The invention reduces labor-intensive procedures and minimizes the need for specialized tools, leading to cost savings. Additionally, by facilitating early detection of defects, it helps prevent costly unplanned repairs or premature component replacements.
• Environmental Benefits: As the method eliminates the use of radiation-based techniques, it reduces environmental concerns associated with traditional inspection methods. This aligns with sustainability goals and reduces the environmental footprint of turbine maintenance activities.

TEST RESULT:
[0046] Fig. 3 illustrates a test results of Defect signals of low-pressure steam turbine blade using vibro-thermography for defects in accordance with an embodiment of the present disclosure. The defect signals may show variations in intensity, frequency, or other parameters, providing insights into the nature and severity of defects within the turbine blades. These signals serve as crucial data for analyzing and diagnosing the structural integrity of the blades, aiding in the decision-making process for maintenance or repair actions.
WORKING OF INVENTION:
[0047] During the overhauling of a steam turbine rotor, it is required to carry out Non-destructive testing of all the moving blades to make sure that they are free of any defects. LP blades are most prone to root cracks. This method can be used at factory or at site for carrying out the examination of low-pressure turbine blades for detection of surface/ sub-surface cracks if any
[0048] The above description does not provide specific details of the manufacture or design of the various components. Those of skill in the art are familiar with such details, and unless departures from those techniques are set out, techniques, known, related art or later developed designs and materials should be employed. Those in the art are capable of choosing suitable manufacturing and design details.
[0049] Further, the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the disclosure. It will be appreciated that several of the above-disclosed and other features and functions, or alternatives thereof, may be combined into other fixture or applications. Various presently unforeseen or unanticipated alternatives, modifications, variations, or improvements therein may subsequently be made by those skilled in the art without departing from the scope of the present disclosure as encompassed by the following claims.
[0050] The claims, as originally presented and as they may be amended, encompass variations, alternatives, modifications, improvements, equivalents, and substantial equivalents of the embodiments and teachings disclosed herein, including those that are presently unforeseen or unappreciated, and that, for example, may arise from applicants/patentees and others.
[0051] It will be appreciated that variants of the above-disclosed and other features and functions, or alternatives thereof, may be combined into many other different fixture or applications. Various presently unforeseen or unanticipated alternatives, modifications, variations, or improvements therein may be subsequently made by those skilled in the art which are also intended to be encompassed by the following claims.
, Claims:We Claim:
1. A method(100) of inspection of low-pressure steam turbine blade using vibro-thermography for defects, the method(100) comprising:
mounting(102), a Low Pressure (LP) turbine blade for testing and defect detection;
applying(104), a predetermined pressure to a LP turbine blade using a pneumatic cylinder mounted on a cross beam to ensure secure fixation during testing
introducing(106), an ultrasound energy into a blade root for excitation to facilitate defect detection;
capturing(108), the thermal images of the LP turbine blade during ultrasound excitation to monitor temperature variations; and
processing(110), the captured thermal images to form a defect signal indicative of structural anomalies within the LP turbine blade.
2. The method as claimed in the claim 1,wherein the pressure applied by the pneumatic cylinder ensures stable positioning of the LP turbine blade for accurate testing.
3. The method as claimed in the claim 1,wherein the ultrasound energy is introduced into the blade root to induce controlled vibration for defect detection.
4. The method as claimed in the claim 1,wherein thermal imaging cameras are utilized to capture thermal images of the LP turbine blade from multiple angles during ultrasound excitation.
5. The method as claimed in the claim 1,wherein the captured thermal images are processed using image processing algorithms to identify and analyse temperature variations associated with defects within the LP turbine blade.
6. The system for inspection of low-pressure steam turbine blade using vibro-thermography for defects, the system comprising:
a fixture with a wooden base for securing the LP turbine blade, ensuring stability during evaluation;
a pneumatic cylinder housing an ultrasonic transducer mounted on a cross beam for applying pressure to secure the LP turbine blade during testing;
an ultrasound excitation system configured to introduce ultrasound energy into the blade root for controlled excitation;
a thermal imaging camera positioned to capture thermal images of the LP turbine blade during ultrasound excitation; and
a processing unit for analyzing the captured thermal images to form a defect signal indicative of structural anomalies within the LP turbine blade.