Researchers Submit Patent Application, "Hardware and Method for Implementation of in Situ Acoustic Thermograph Inspections", for Approval (USPTO...
Researchers Submit Patent Application, "Hardware and Method for Implementation of in Situ Acoustic Thermograph Inspections", for Approval (USPTO 20160069829)
By a News Reporter-Staff News Editor at Politics & Government Week -- From
Washington, D.C.
, VerticalNews journalists report that a patent application by the inventors Ruhge, Forrest R. (
Orlando, FL
); Hatcher, JR., Clifford (
Orlando, FL
); DeAscanis, Joshua (
Oviedo, FL
); Williams,
James P. (
Orlando, FL
); Shannon, Robert G. (
Oviedo, FL
), filed on September 9, 2014, was made available online on March 17, 2016.
No assignee for this patent application has been made.
News editors obtained the following quote from the background information supplied by the inventors: "This invention relates generally to a system and method for performing thermograph inspection of turbine blades and, more particularly, to a system and method for performing acoustic thermograph inspection of turbine blades without removing the blades from the turbine so as to eliminate the need for costly blade removal to perform the inspection.
"The world's energy needs continue to rise which provides a demand for reliable, affordable, efficient and environmentally-compatible power generation. A turbine engine is one known machine that provides efficient power, and often has application for an electric generator in a power plant, or engines in an aircraft or a ship. A typical gas turbine engine includes a compressor section, a combustion section and a turbine section. The compressor section provides a compressed air flow to the combustion section where the air is mixed with a fuel, such as natural gas, and ignited to create a hot working gas. The working gas expands through the turbine section and is directed across rows of blades therein by associated vanes. As the working gas passes through the turbine section, it causes the blades to rotate, which in turn causes a shaft to rotate, thereby providing mechanical work.
"Maintaining the structural integrity of the blades in a turbine is important for proper operation of the turbine. Thus, it is very important to periodically check the blades for signs of deterioration, such as cracks and defects. One known technique for testing for material defects in the blades includes treating the blades with a dye penetrant so that the dye enters any crack or defect that may be present. The blades are then cleaned, and the structure is treated with a powder that causes the dye remaining in the cracks to wick into the powder. An ultraviolet (UV) light source is used to inspect the material to observe locations on the component that fluoresces as a result of the dye. This technique is disadvantageous, however, because it is inspector intensive and dependent and requires the person to be skilled. Additionally, the dye does not typically penetrate tightly closed cracks or cracks that are not on the surface.
"A second known technique for inspecting a component for defects employs an electromagnetic coil to induce eddy currents in the blade. The coil is moved around on the blade, and the eddy current pattern changes at a crack or other defect. When the eddy current pattern changes a complex impedance in the coil changes, which can be observed on an oscilloscope. This technique has the drawback that it is also very operator intensive, slow and tedious.
"A third known technique employs thermal imaging of the component to identify the defects. Typically, a heat source, such as a flash lamp or a heat gun, is used to direct a planar pulse of heat to the surface of the component. The material of the component absorbs the heat, and emits reflections in the infrared wavelengths. Certain types of defects will cause the surface temperature to cool at a different rate over the defects than for the surrounding areas. A thermal or infrared imaging camera is used to image the component and detect the resulting surface temperature variation. Although this technique has been successful for detecting disbands and corrosion, it is ordinarily not successful at detecting vertical cracks in the material, i.e., those cracks that are perpendicular to the surface. This is because a fatigue crack looks like a knife edge to the planar heat pulse, and therefore no, or minimal, reflections occur from the crack, making the cracks difficult or impossible to see in the thermal image.
"Thermal imaging for detecting defects in a material that is capable of detecting small cracks as well as tightly closed cracks is described in
U.S.
Pat. No. 6,399,948 issued to Thomas et al. on Jun. 4, 2002. However, this technique requires the material that is being inspected to be placed in a thermal imaging system. Thus, if the material to be inspected includes turbine blades, the blades must be removed from the turbine to be inspected. Removal of turbine blades is costly, time-consuming and labor intensive. Thus, there is a need in the art for a system and method that allows for thermal imaging of turbine blades without removing the blades from the turbine."
As a supplement to the background information on this patent application, VerticalNews correspondents also obtained the inventors' summary information for this patent application: "This disclosure describes a system and method for performing acoustic thermography inspection of turbine blades. The system and method include an acoustic thermography stack and a frame that the stack is slidably mounted to. The frame includes an end frame portion with a blade stop, and an air cylinder provides force to move the stack up and down a rail of the frame such that a turbine blade may be clamped between a cap of the stack and the blade stop. The clamped blade is excited using the stack, and an infrared camera is used to detect critical indications in the blade.
"Additional features of the present invention will become apparent from the following description and appended claims, taken in conjunction with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
"FIG. 1 is an illustration of a gas turbine engine;
"FIG. 2 is an illustration of a known turbine blade separated from a gas turbine engine;
"FIG. 3 is an illustration of a cross-sectional view along line 3-3 of the blade shown in FIG. 2;
"FIG. 4 is an illustration of an embodiment of a system for performing acoustic thermography of turbine blades that are part of an assembled steam turbine;
"FIG. 5 is an illustration of the system for performing acoustic thermography where the system is being used inside of an assembled steam turbine;
"FIG. 6 is an illustration of an infrared camera that is being used with the system according to one embodiment; and
"FIG. 7 is an illustration of the infrared camera being used with the system according to another embodiment."
For additional information on this patent application, see: Ruhge, Forrest R.; Hatcher, JR., Clifford; DeAscanis, Joshua; Williams, James P.; Shannon, Robert G. Hardware and Method for Implementation of in Situ Acoustic Thermograph Inspections. Filed September 9, 2014 and posted March 17, 2016. Patent URL: http://appft.uspto.gov/netacgi/nph-Parser?Sect1=PTO2&Sect2=HITOFF&u=%2Fnetahtml%2FPTO%2Fsearch-adv.html&r=3741&p=75&f=G&l=50&d=PG01&S1=20160310.PD.&OS=PD/20160310&RS=PD/20160310
Keywords for this news article include: Energy, Patents, Oil & Gas, Steam Turbine.
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