Patent Application
20130327466
Tubing is employed to transport fluid through a gas turbine engine. Insulated tubing can include an inner metal tube with a surrounding insulation layer. In one example, the insulation layer is made of a solid material. A metal cover surrounds the insulation layer and retains the insulation layer on the inner metal tube.
The metal cover is formed from two flat pieces of metal. The pieces of metal are stamped to form a shell portion having a partial tubing shape. The metal inner tube and the insulation layer are located between two shell portions that are secured together by welding or brazing to form the metal cover. The metal cover is expensive, requires expensive tooling, and can take a long time to create.
A tubing includes an inner tube, an inner middle insulation layer, an outer middle securing layer, and an outer shrinkable cover that shrinks upon exposure to heat.
In a further non-limiting embodiment of the foregoing tubing, an inner tube is made of one of a nickel alloy, a titanium alloy, a nickel-chromium alloy, and stainless steel.
In a further non-limiting embodiment of the foregoing tubing, an inner tube has an outer diameter of about 0.375 inch to about 0.5 inch.
In a further non-limiting embodiment of the foregoing tubing, an inner middle insulation layer includes two outer layers and an insulation filler located therebetween.
In a further non-limiting embodiment of the foregoing tubing, two outer layers include ceramic fibers and the insulation filler has a chalky consistency.
In a further non-limiting embodiment of the foregoing tubing, an insulation filler is contained in chambers defined between the two outer layers, and the chambers are defined by stitching.
In a further non-limiting embodiment of the foregoing tubing, an inner middle insulation layer has a thickness of about 0.14 inch.
In a further non-limiting embodiment of the foregoing tubing, an outer middle securing layer is a ceramic tape layer.
In a further non-limiting embodiment of the foregoing tubing, an outer middle securing layer has a thickness of about 0.32 inch.
In a further non-limiting embodiment of the foregoing tubing, an outer shrinkable cover is polytetrafluoroethylene.
In a further non-limiting embodiment of the foregoing tubing, an outer shrinkable cover has an outer diameter of about 0.68 inch to about 0.775 inch.
A tubing includes an inner tube of metal, an inner middle insulation layer, an outer middle securing layer formed of a ceramic tape layer, and an outer shrinkable cover of polytetrafluoroethylene that shrinks upon exposure to heat.
In a further non-limiting embodiment of the foregoing tubing, the inner tube is made of one of a nickel alloy, a titanium alloy, a nickel-chromium alloy, and stainless steel.
In a further non-limiting embodiment of the foregoing tubing, the inner middle insulation layer includes two outer layers and an insulation filler located therebetween, and the two outer layers include ceramic fibers and the insulation filler has a chalky consistency.
In a method of making a tubing, the method includes the steps of positioning an inner middle insulation layer around an inner tube and positioning an outer middle securing layer over the inner middle insulation layer to retain the inner middle insulation layer. The method also includes the steps of pulling an outer shrinkable cover over the outer middle securing layer and then heating areas of the outer shrinkable cover to shrink the outer shrinkable cover.
In a further non-limiting embodiment of the foregoing method, the inner tube is made of one of a nickel alloy, a titanium alloy, a nickel-chromium alloy, and stainless steel.
In a further non-limiting embodiment of the foregoing method, the step of positioning the inner middle insulation layer around the inner tube includes wrapping the inner middle insulation layer around the inner tube such that edges of the inner middle insulation layer contact or overlap, where the inner middle insulation layer includes two outer layers and an insulation filler located therebetween, and the two outer layers includes ceramic fibers and the insulation filler has a chalky consistency.
In a further non-limiting embodiment of the foregoing method, the step of positioning the outer middle securing layer over the inner middle insulation layer includes wrapping the outer middle securing layer around the inner middle insulation layer, and the outer middle securing layer is formed of ceramic tape.
In a further non-limiting embodiment of the foregoing method, the outer shrinkable cover includes small diameter portions and large diameter portions, and the small diameter portions are located over straight portions of the tubing and the large diameter portions are located over curved portions of the tubing, where the outer shrinkable cover is polytetrafluoroethylene.
In a further non-limiting embodiment of the foregoing method, the step of then heating the areas of the outer shrinkable cover includes applying heat at a temperature of about 750° F. for about one minute to about one and a half minutes at the areas of the tubing.
In a further non-limiting embodiment of the foregoing method, the areas of the outer shrinkable cover are about one square inch.
These and other features of the present invention can be best understood from the following specification and drawings, the following of which is a brief description.
During operation, air is compressed in the low-pressure compressor section 16 and the high-pressure compressor section 18. The compressed air is then mixed with fuel and burned in the combustion section 20. The products of combustion are expanded across the high-pressure turbine section 22 and the low-pressure turbine section 24.
The high-pressure compressor section 18 and the low-pressure compressor section 16 include rotors 26 and 28, respectively. The rotors 26 and 28 are configured to rotate about the axis 12, driving the compressors 16 and 18. The compressors 16 and 18 include alternating rows of rotating compressor blades 30 and static airfoils or vanes 32.
The high-pressure turbine section 22 includes a rotor 34 that is rotatably coupled to the rotor 26, and the low-pressure turbine section 24 includes a rotor 36 that is rotatably coupled to the rotor 28. The rotors 34 and 36 are configured to rotate about the axis 12 in response to expansion. When rotated, the rotors 34 and 36 drive the high-pressure compressor section 18 and the low-pressure compressor section 16. The rotor 36 also rotatably drives a fan 38 of the fan section 14. The turbines 22 and 24 include alternating rows of rotating airfoils or turbine blades 40 and static airfoils or vanes 42.
The gas turbine engine 10 also includes at least one fluid system 44 including tubing 46 (shown in
The tubing 46 includes an insulation layer 50 that is located outside the inner tube 48. In one example, the insulation layer 50 provides thermal insulation. As shown in
In one example, the insulation filler 54 has a chalky consistency and is flexible. In one example, the insulation filler 54 is MIN-K®, sold by Johns-Manville Corporation of New York, N.Y. In one example, the two outer layers 52 are formed of a heavy thermal fabric including ceramic fibers. In one example, the two outer layers 52 are Nextel woven fabric 312, sold by 3M of St. Paul, Minn.
The insulation layer 50 is custom cut to size to fit around an outer surface 58 of the inner tube 48. The insulation layer 50 is then wrapped around the outer surface 58 of the inner tube 48 such that edges 60 of the insulation layer 50 contact or overlap.
Once the insulation layer 50 is wrapped around the inner tube 48, tape is wrapped around the insulation layer 50 to form a tape layer 62 that secures the contacting or overlapping edges 60 of the insulation layer 50 together and retains the insulation layer 50 in place. In one example, the tape layer 62 has a thickness of about 0.32 inch (0.81 cm). In one example, the tape layer 62 is a ceramic tape layer.
A shrinkable cover 64 is then pulled over the tape layer 62. Once shrunk, the shrinkable cover 64 provides a seal over the insulation layer 50. In one example, the shrinkable cover 64 is made of a shrinkable fluorocarbon that shrinks at a certain temperature. In one example, the shrinkable cover 64 is made of polytetrafluoroethylene (PTFE). The shrinkable cover 64 is pulled over the tape layer 62 in sections 64a and 64b.
As shown in
The shrinkable cover 64 is then heated, causing the shrinkable cover 64 to shrink and reduce in size, creating a seal over the insulation layer 50. A heating element 66, for example a heat gun, applies heat to an area of the shrinkable layer 64 to shrink the area of the shrinkable cover 64 that is exposed to the heat. In one example, the heating element 66 applies heat at a temperature of about 750° F. (398.9° C.) for about one minute to about one and a half minutes at each area of the tubing 46. In one example, each area of the tubing 46 is about one square inch. The shrinkage and reduction in size of the shrinkable cover 64 secures the layers of the tubing 46 together and provides a tight seal around the insulation layer 50 and at ends 68 of the tubing 46.
Returning to
In one example shown in
The tubing 46 provides about 0.39 BTU protection to the fluid flowing through the tubing 46 to temperatures up to about 1000° F. (537.7° C.). The tubing 46 also provides for a quick assembly with a reduced cost.
In another example, the insulation layer 50 and the tape layer 62 are wrapped around a component of the gas turbine engine 10 to provide insulation, and the shrinkable cover 64 is located over the tape layer 62 and heated to seal the layers over the component.
The foregoing description is only exemplary of the principles of the invention. Many modifications and variations are possible in light of the above teachings. It is, therefore, to be understood that within the scope of the appended claims, the invention may be practiced otherwise than using the example embodiments which have been specifically described. For that reason the following claims should be studied to determine the true scope and content of this invention.
