Patent Application
20180356438
This application claims the benefit of the IN Application No. 201711020311 filed Jun. 9, 2017, which is incorporated herein by reference in its entirety.
The subject matter disclosed herein generally relates to pitot tubes. More specifically, the present disclosure relates to the formation of pitot tubes.
A pitot tube is widely used to determine airspeed of an aircraft or other vehicle, or to measure air or gas velocities in industrial applications. In particular, by measuring stagnation pressure of a fluid driven into the pitot tube, together with a measured static pressure, the airspeed of the aircraft can be determined. In certain flight conditions, the pitot tube may be subject to ice accumulation from moisture in the air. For this reason, pitot tubes are equipped with heating elements to prevent such ice accumulation. Further, in other conditions, the pitot tube may ingest ice crystals which then accumulate inside of the pitot tube and cause failure in its operation.
A typical pitot tube is substantially cylindrical with an internal diameter containing the heating elements, or coils. Forward of the heating elements is a tip portion that extends radially from forward tip portion to an outer diameter of the pitot tube. An exterior of the typical tube is cylindrical along its length to the inlet. Such a tube has a large surface area of material in the tip portion forward of the heater, and is difficult to heat effectively and therefore to prevent ice accumulation thereon. Further, a large inlet diameter allows for proportionally more ice crystals to be ingested by the pitot tube. Such ingested ice crystals must be melted by the heating elements and drained from the pitot tube.
According to one aspect of an exemplary embodiment, a pitot tube includes a substantially cylindrical body portion having an interior defining a flow passage. A tip portion extends along a pitot tube axis from the body portion. The tip portion includes a high thermal conductive insert. The body portion and the tip portion including the high thermal conductive insert are integrally formed.
In addition to one or more of the features described above, or as an alternative, in further embodiments the high thermal conductive insert is formed of graphite or carbon graphite.
In addition to one or more of the features described above, or as an alternative, in further embodiments the high thermal conductive insert is formed of annealed pyrolytic graphite.
In addition to one or more of the features described above, or as an alternative, in further embodiments the high thermal conductive insert is formed from a first material having a first melting temperature and the cylindrical body portion is formed from a second material having a second melting temperature, the first melting temperature being higher than the second melting temperature.
In addition to one or more of the features described above, or as an alternative, in further embodiments the body portion is formed of nickel.
According to another aspect of an exemplary embodiment, a method of forming a hybrid pitot tube includes positioning a high thermal conductive insert within a mold and injecting a flowable material into the mold. The flowable material when cooled forms a core element extending at least partially into the high thermal conductive insert. The method further includes forming a secondary element about the mold. During formation of the secondary element, the core element is eliminated. A continuous cast body is formed about the high thermal conductive insert. The continuous cast body is formed from a first material and the high thermal conductive insert is formed from a second material. The continuous cast body is formed into a pitot tube.
In addition to one or more of the features described above, or as an alternative, in further embodiments the high thermal conductive insert includes a cavity and positioning the high thermal conductive insert within the mold further comprises mounting a member extending from the mold within the cavity.
In addition to one or more of the features described above, or as an alternative, in further embodiments the flowable material injected into the mold is a molten wax.
In addition to one or more of the features described above, or as an alternative, in further embodiments forming a secondary element about the mold further comprises: removing the high thermal conductive insert and the core element from the mold; dipping the high thermal conductive insert and the core element into a slurry; and curing the slurry.
In addition to one or more of the features described above, or as an alternative, in further embodiments curing the slurry causes the core element to melt and separate from the slurry and the high thermal conductive insert.
In addition to one or more of the features described above, or as an alternative, in further embodiments the secondary element comprises a ceramic material.
In addition to one or more of the features described above, or as an alternative, in further embodiments forming a continuous cast body about the high thermal conductive insert, further comprises: installing the high thermal conductive element and the secondary element into another mold; pouring a molten metal material into a hollow interior of the secondary element; and removing the secondary element after the molten metal material has cooled and solidified.
In addition to one or more of the features described above, or as an alternative, in further embodiments forming a continuous cast body about the high thermal conductive insert, further comprises: pouring additional molten metal material into the hollow interior of the secondary element, wherein the additional molten metal material adjoins the cooled and solidified molten metal material to form a continuous cast body.
In addition to one or more of the features described above, or as an alternative, in further embodiments the high thermally conductive tip insert is encapsulated within the continuous cast body.
In addition to one or more of the features described above, or as an alternative, in further embodiments the high thermal conductive insert is formed of graphite or carbon graphite.
In addition to one or more of the features described above, or as an alternative, in further embodiments the high thermal conductive insert is formed of annealed pyrolytic graphite.
In addition to one or more of the features described above, or as an alternative, in further embodiments the continuous cast body is formed of nickel.
These and other advantages and features will become more apparent from the following description taken in conjunction with the drawings.
The subject matter, which is regarded as the invention, is particularly pointed out and distinctly claimed in the claims at the conclusion of the specification. The foregoing and other features, and advantages of the invention are apparent from the following detailed description taken in conjunction with the accompanying drawings in which:
The detailed description explains embodiments of the disclosure, together with advantages and features, by way of example with reference to the drawings.
With reference now to
In an embodiment, the pitot tube 10 has a hybrid construction of multiple materials. For example, the body 12 of the pitot tube 10 may be formed from a first material and the tip portion 14 of the pitot tube 10 may be formed from or may include a second material. The first and second materials may be coupled together, or alternatively may be integrally formed during manufacturing of the pitot tube 10. In an embodiment, the second material is provided in the form of an insert 30, best shown in
Once the insert 30 is installed within the mold 34, the cavity 32 of the mold 34 is filled with a core material 42, such as a molten wax for example (see
The preform is then dipped into a secondary material. The core material 42 acts as a base to support the secondary material. A coating of the secondary material 44, best shown in
A molten metal material 46 is poured into the hollow interior defined by the secondary material 44. The molten material 46 is configured to fill the void left by melting the core element 42. In the illustrated, non-limiting embodiment, the metal 46 is added in two stages. However, embodiments where the metal is added during a single stage are also contemplated herein. With reference to
The first application or stage of molten metal material 46 forms the cylindrical body 12 and an exterior of the tip end 14 of the pitot tube 10. Additional molten metal material may then be applied, such as during a second stage as shown in
The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the disclosure. As used herein, the singular forms “a”, “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “comprises” and/or “comprising,” when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, element components, and/or groups thereof.
While the disclosure is provided in detail in connection with only a limited number of embodiments, it should be readily understood that the disclosure is not limited to such disclosed embodiments. Rather, the disclosure can be modified to incorporate any number of variations, alterations, substitutions or equivalent arrangements not heretofore described, but which are commensurate with the spirit and scope of the disclosure. Additionally, while various embodiments of the disclosure have been described, it is to be understood that the exemplary embodiment(s) may include only some of the described exemplary aspects. Accordingly, the disclosure is not to be seen as limited by the foregoing description, but is only limited by the scope of the appended claims.
| Number | Date | Country | Kind |
|---|---|---|---|
| 201711020311 | Jun 2017 | IN | national |
