Patent Description:
Many components of gas turbine engines require lubrication and cooling. Such components may be shaft bearings, gear boxes, and the like. Gas turbine engines typically comprise an oil tank and an oil pump in fluid communication with an oil circuit configured to circulate oil to these components requiring lubrication. Oil circuits are not always leak proof and air that enters the circuit can mix with the oil. The resulting air-oil mixture is thus routed to the components and can affect the lubricating efficiency. A de-aerator is thus typically used to extract any air from the air-oil mixture before the oil is routed back through the oil circuit. However, existing de-aerators are not always able to extract all the air from the air-oil mixture.

What is needed is an improved de-aerator.

<CIT> discloses a prior art de-aerator as set forth in the preamble of claim <NUM>.

<CIT> discloses a prior art lubrication system and method, and a vortex flow separator for use therewith.

According to an aspect of the present disclosure, there is provided a de-aerator for an oil system of a gas turbine engine as recite in claim <NUM>.

There is also provided a lubrication system for a gas turbine engine as recited in claim <NUM>.

For example, aspects and/or embodiments of the present disclosure may include any one or more of the individual features or elements disclosed above and/or below alone or in any combination thereof.

<FIG> and <FIG> illustrate a gas turbine engine <NUM> of a type preferably provided for use in subsonic flight, generally comprising in serial flow communication a fan <NUM> through which ambient air is propelled, a compressor section <NUM> for pressurizing the air, a combustor <NUM> in which the compressed air is mixed with fuel and ignited for generating an annular stream of hot combustion gases, and a turbine section <NUM> for extracting energy from the combustion gases. The present disclosure may be used within conventional through-flow engines, or reverse flow engines, and gas turbine engine types such as turbofan engines, turboprop engines, turboshaft engines, auxiliary power unit (APU), and the like.

The engine <NUM> further comprises one or more fluid systems, such as a lubricant system <NUM> that circulates lubricant to both lubricate and cool components; e.g., bearings, gears (e.g., within a gearbox), and other components. The lubricant system <NUM> includes a lubricant pump <NUM>, a lubricant tank <NUM>, a de-aerator <NUM>, and a scavenge pump <NUM> all in fluid flow communication with each other. The lubricant system <NUM> includes piping <NUM> that interconnects the aforesaid components. In some embodiments, the de-aerator <NUM> may be disposed in the lubricant tank <NUM> and in other embodiments, the de-aerator <NUM> may be disposed in-line outside the lubricant tank <NUM>. Regardless of where the de-aerator <NUM> is disposed, the space available for the de-aerator <NUM> is often limited. Even in those instances where space is not constrained, a smaller de-aerator <NUM> will likely be advantageously lower in weight.

<FIG> diagrammatically illustrates a lubricant system <NUM> circuit. Lubricant within the lubricant tank <NUM> is pumped to an elevated pressure via a mechanical pump <NUM> and is supplied to the engine <NUM> where it is specifically applied to various components for lubrication and/or cooling purposes. Once the lubricant has engaged one or more of the engine components, a scavenge pump <NUM> is employed to recover the lubricant from the engine <NUM>. Within the circuit, air is often drawn into the circuit and becomes entrained within the lubricant. In the lubricant system <NUM> circuit shown in <FIG>, the lubricant passes from the scavenge pump <NUM> into the de-aerator <NUM>. The de-aerator <NUM> removes the entrained air and passes the de-aerated lubricant back into the lubricant tank <NUM> and the cycle repeats itself. The lubricant system <NUM> circuit shown in <FIG> is diagrammatic and the present disclosure is not limited to this diagrammatic lubricant circuit and/or the components included. In many instances, additional components such as a heat exchanger and the like may be included.

<FIG> is a diagrammatic illustration of a de-aerator <NUM> embodiment according to the present disclosure. The de-aerator <NUM> includes a fluid inlet <NUM>, a body <NUM>, a helical fluid passage <NUM>, and one or more fluid outlets <NUM>. In some embodiments, the de-aerator <NUM> may also include one or more of a fluid collection body <NUM>, a vent tube <NUM>, and one or more partitions <NUM>.

The de-aerator body <NUM> is configured to contain fluids for de-aerating and includes a cover panel <NUM>, at least one sidewall <NUM>, a base panel <NUM>, and an internal cavity <NUM>. The cover panel <NUM>, sidewall <NUM>, and base panel <NUM> each include an interior surface 56I, 58I, 60I and an exterior surface 56E, 58E, 60E. The body <NUM> may be described as having a center axis <NUM> that extends along a y-axis, and has a width that extends along an X-axis, where the X and Y axes are orthogonal axes. The cover panel <NUM> is disposed at a first axial end <NUM> of the body <NUM> and the base panel <NUM> is disposed at a second axial end <NUM> of the body <NUM>, opposite the first axial end <NUM>. The base panel <NUM> is connected to the sidewall <NUM> at the second axial end <NUM>. In the embodiment shown in <FIG>, the de-aerator body <NUM> is substantially cylindrically shaped having a single sidewall <NUM>. The present disclosure is not, however, limited to de-aerators <NUM> having a cylindrical shape. For example, the de-aerator body <NUM> may be frustoconical or may have linear side walls (e.g., rectangular, square, pentagonal, or octagonal) or may vary in diameter in some portions.

Referring to <FIG>, the fluid inlet <NUM> is disposed adjacent the cover panel <NUM> at the first axial end <NUM>. The fluid inlet <NUM> is configured to have an internal flow passage <NUM> that directs fluid tangentially into internal cavity <NUM> and into the helical fluid passage <NUM>, at an axial position near the first axial end <NUM>; e.g., the fluid inlet direction is predominantly circumferentially in an X-plane and may in some embodiments have an axial component (Y-axis) substantially smaller than the X-plane circumferential component. Hence, the fluid inlet <NUM> directs air-entrained fluid in a direction along the circumferential periphery of the internal cavity <NUM> (into the helical fluid passage <NUM>). The internal flow passage <NUM> is not limited to any particular geometry. Examples of acceptable inlet internal flow passage <NUM> geometries include circular, rectangular, oval, and the like. In some embodiments, the inlet internal flow passage <NUM> may include helical grooving ("swirl grooves <NUM>") in the wall that defines the inlet internal flow passage <NUM> (See <FIG>). The swirl grooves <NUM> are configured to impart a swirling motion to at least part of the inlet fluid flow as it is directed tangentially into the internal cavity <NUM> of the body <NUM>. The swirl grooves <NUM> can be formed in several different configurations, for example, a semi-circular channel, etc. The swirl grooves <NUM> are understood to increase the residency time of the fluid passing through the de-aerator <NUM> and to facilitate the liberation of air from the air-entrained fluid.

The helical fluid passage <NUM> is configured to contain the fluid entering the internal cavity <NUM> of the de-aerator <NUM> and direct it in a helical path between an entry end <NUM> (see <FIG>) and an exit end <NUM>. The helical fluid passage <NUM> including a plurality of circumferential turns between the entry and exit ends <NUM>, <NUM>, axially descending toward the second axial end <NUM> of the body <NUM>. Each circumferential turn extends once circumferentially around the center axis <NUM>. As a result of the helical fluid passage <NUM> configuration, centrifugal force acts on the fluid forcing the liquid portion of the fluid (with its mass greater than air) radially outwardly and causing separation of the liquid portion of the fluid from the entrained air portion of the fluid.

Referring to <FIG> and <FIG>, in some embodiments the helical fluid passage <NUM> may be formed independent of a vent tube <NUM> (not shown in <FIG>). In these embodiments, the helical fluid passage <NUM> again uses the sidewall interior surface 58I as the outer radial surface of the passage <NUM>, and an inner radial wall <NUM> forms the inner radial surface of the passage <NUM>. In some embodiments (e.g., as shown in <FIG>), a single helically extending panel <NUM> forms the axially upper and lower surfaces of the passage <NUM> except towards the axial ends of the passage <NUM>. In other embodiments, a plurality of helically extending panels <NUM> form the axially upper and lower surfaces of the passage <NUM> (e.g., as shown in <FIG>). In these embodiments, vent apertures <NUM> may be disposed in the inner radial wall <NUM> of the passage <NUM> to permit the passage of air out of the passage <NUM>. <FIG> illustrates a vent tube <NUM> disposed in a central region <NUM> radially inside of the helical fluid passage <NUM>.

The de-aerator <NUM> embodiment shown in <FIG> includes a helical fluid passage <NUM> with a first section 46A and a second section 46B. The first section 46A begins at the inlet internal flow passage (not shown in <FIG>) and extends to the second section 46B. The second section 46B ends at the helical fluid passage exit end <NUM> open to the bottom of the de-aerator <NUM>. The first section 46A is formed by a helically extending panel <NUM> that extends between the interior surface 58I of the sidewall <NUM> and an exterior surface 52E of a centrally disposed vent tube <NUM>. Hence, the outer radial surface of the helical fluid passage <NUM> is the sidewall interior surface 58I, the inner radial surface of the helical fluid passage <NUM> is the exterior surface 52E of the vent tube <NUM>. In this embodiment, the vent tube <NUM> does not extend substantially to the bottom of the de-aerator <NUM>, but rather terminates approximately in the axial middle of the de-aerator <NUM>. The second section 46A of the helical fluid passage <NUM> includes an inner radial wall <NUM> that does not fully enclose the helical fluid passage <NUM>. As a result, air liberated from the entrained air fluid is free to pass over the inner radial wall <NUM>, into a central region <NUM> of the de-aerator <NUM>, and pass thereafter into the vent tube <NUM> for passage out of the de-aerator <NUM>. The de-aerator <NUM> embodiment shown in <FIG> is an example and is therefore non-limiting. As an alternative to the embodiment shown in <FIG>, a de-aerator <NUM> may not include a helical fluid passage <NUM> with first and second sections, but rather has a vent tube <NUM> that extends further toward the second axial end <NUM> and has a helically extending panel <NUM> that extends between the interior surface 58I of the sidewall <NUM> and an exterior surface 52E of a centrally disposed vent tube <NUM> as described above. In these embodiments, vent apertures may be disposed in the vent tube <NUM> to allow air to pass from the helical fluid passage <NUM> into the vent tube <NUM>.

Referring to <FIG>, in some embodiments the helical fluid passage <NUM> may be formed in part by a helical groove <NUM> disposed in the sidewall interior surface 58I. The present disclosure is not limited to any particular groove <NUM> configuration within the sidewall interior surface 58I.

The helical fluid passage <NUM> examples shown in <FIG> are examples of how the helical fluid passage <NUM> may be configured and the present disclosure is not limited to these examples.

The air liberated from the air entrained fluid collects centrally before exiting the de-aerator <NUM>. As indicated above, some embodiments may include a vent tube <NUM> that is integral with the helical fluid passage <NUM>, extending axially into the de-aerator <NUM> to the lower axial region of the de-aerator body <NUM>. The vent tube <NUM> may extend axially through the cover panel <NUM> and continue outside the de-aerator <NUM> for venting elsewhere (e.g., see <FIG>). In other embodiments, the de-aerator <NUM> may include a central region <NUM> defined at least in part by the enclosed helical fluid passage <NUM> (e.g., see <FIG>). Separated air may exit the de-aerator <NUM> via the central region <NUM>, and the cover panel <NUM> may include a tube either connected to the cover panel <NUM> or extending through the cover panel <NUM> that provides an exit air passage for venting outside of the de-aerator <NUM>.

The de-aerator <NUM> includes at least one partition <NUM> disposed at or below the exit of the helical fluid passage <NUM> and spaced above the base panel <NUM> of the de-aerator <NUM>. The partition <NUM> has an upper surface 54U, a lower surface <NUM>, a thickness <NUM> extending between the upper and lower surfaces 54U, <NUM>, and a circumferential edge <NUM> (e.g., see <FIG>). The partition <NUM> may extend within the internal cavity <NUM> in a plane that is substantially perpendicular to the central axis <NUM>. Alternatively, in some embodiments a partition <NUM> may extend within the internal cavity <NUM> in a plane that canted (i.e., not perpendicular) relative to the central axis <NUM>. As will be detailed below, in some embodiments the circumferential edge <NUM> of the partition <NUM> may be either contiguous with, or connected to, the interior sidewall surface 58I (e.g., se <FIG>); i.e., no purposeful fluid passage is disposed between the circumferential edge <NUM> of the partition <NUM> and the interior sidewall surface 58I and the partition <NUM> extends entirely across the internal cavity <NUM> from sidewall <NUM> to sidewall <NUM>. In some embodiments, at least a part of the circumferential edge <NUM> of the partition <NUM> may be spaced apart from the interior sidewall surface 58I to form a fluid passage between the circumferential edge <NUM> of the partition <NUM> and the interior sidewall surface 58I (see <FIG>). During operation, fluid will exit the helical fluid passage <NUM> at a circumferential fluid velocity and will encounter the partition(s) <NUM>. The partition(s) <NUM> in combination with the body sidewalls <NUM> are configured to slow the velocity of the fluid exiting the helical fluid passage <NUM>, disperse the fluid, and thereby provide additional opportunity for any air entrained within the fluid to separate and enter the vent tube <NUM> or the central cavity for passage out of the de-aerator <NUM>.

The de-aerator <NUM> embodiments shown in <FIG>, <FIG>, and <FIG> include a single partition <NUM> having an upper surface 54U and a lower surface <NUM> and a plurality of apertures <NUM> extending through the thickness <NUM> of the partition <NUM> between the upper and lower surfaces 54U. The partition <NUM> shown in <FIG> and <FIG> have slot-like apertures <NUM> extending through the partition <NUM> that vary in size. The apertures <NUM> may be disposed in patterns concentric about the central axis <NUM> of the de-aerator <NUM>; e.g., with a first concentric pattern disposed radially inside of a second concentric pattern. The partitions <NUM> shown in <FIG>, and <FIG> include a plurality of circular apertures <NUM> extending through the partition <NUM>. In <FIG> the circular apertures <NUM> are all the same diameter but in some embodiments the apertures <NUM> may include different diameter apertures <NUM>. The present disclosure is not limited to any particular partition aperture <NUM> configuration or any particular number of apertures <NUM>. The number and configuration of the apertures <NUM> may be chosen based on the fluid volumetric rate through the de-aerator <NUM> to ensure constant fluid volumetric rate through the de-aerator <NUM> even under maximum flow conditions. The de-aerator <NUM> embodiments shown in <FIG>, <FIG>, and <FIG> include a pair of partitions <NUM> configured in the manner described above.

<FIG> illustrates a de-aerator <NUM> having a partition <NUM> without apertures <NUM> in an arrangement outside the wording of the claims. This partition <NUM> is configured so that at least a part of the circumferential edge <NUM> of the partition <NUM> is spaced apart from the interior sidewall surface 58I to form a fluid passage between the circumferential edge <NUM> of the partition <NUM> and the interior sidewall surface 58I.

The partition <NUM> examples described above are provided to illustrate partition <NUM> configurations and the present disclosure is not limited to these examples. For example, in alternative embodiments a partition <NUM> may include more than one aperture configuration (e.g., slots and circles), or a partition <NUM> may include apertures <NUM> and may be configured so that at least a part of the circumferential edge <NUM> of the partition <NUM> is spaced apart from the interior sidewall surface 58I to form a fluid passage there between, or a first partition <NUM> may have a first configuration (e.g., including apertures <NUM> - see <FIG>) and a second partition <NUM> differently configured (e.g., circumferential edge passages - see <FIG>), or any combination thereof.

Partition <NUM> configurations may be chosen to create a fluid flow with decreased velocity that falls gravimetrically to the base of the de-aerator <NUM>. For example, the thickness <NUM> (see <FIG>) of any of these partition <NUM> embodiments may be greater or lesser to improve fluid flow into the base of the de-aerator <NUM> that facilitates de-aeration.

The de-aerator <NUM> may include one or more fluid outlets <NUM> disposed in the sidewall <NUM> (e.g., see <FIG>) or one or more fluid outlets <NUM> disposed in the base panel <NUM> (e.g., see <FIG>). The present disclosure is not limited to any particular fluid outlet geometry or positioning. For example, the fluid outlets <NUM> shown in <FIG> have different oval-like configurations. The oval-like fluid outlets <NUM> shown in <FIG> have their long axes extending substantially parallel to the central axis <NUM> of the de-aerator <NUM>, whereas the oval-like fluid outlets <NUM> shown in <FIG> have their short axes extending substantially parallel to the central axis <NUM> of the de-aerator <NUM>. In some embodiments, a surface of the fluid outlets <NUM> may be flush with the interior surface of the base panel <NUM> (e.g., see <FIG>). In some embodiments, the fluid outlets <NUM> may not be flush with the interior surface of the base panel <NUM> (e.g., see <FIG>); i.e., spaced a distance axially up from the interior surface of the base panel <NUM>.

In some embodiments, the de-aerator <NUM> may include a fluid collection body <NUM> disposed radially outside of the sidewalls <NUM>. The fluid collection body <NUM> is generally concentric with, but radially spaced apart from, the sidewall exterior surface 58E to form an annular cavity there between; e.g., see <FIG> and <FIG>. In these embodiments, piping or other conduit means may be in communication with the fluid collection body <NUM> to receive de-aerated fluid therefrom.

In some embodiments, the cover panel <NUM> may be an independent element that is configured for attachment to the one or more sidewalls <NUM>. For example, the cover panel <NUM> diagrammatically shown in <FIG> is independent of the de-aerator body <NUM> and is configured for attachment to the de-aerator body <NUM>. In the embodiment shown in <FIG>, the vent tube <NUM> is integrally formed with the cover panel <NUM>. A sealing element (e.g., an O-ring or the like) may be used to create a fluidic seal between the cover panel <NUM> and the de-aerator body <NUM>.

In some embodiments, one or more elements of the de-aerator <NUM> may be produced independently of other elements and the de-aerator <NUM> formed as an assembly. An example of this configuration is described above where the cover panel <NUM> and the vent tube <NUM> are independent of the de-aerator body <NUM>. In some embodiments, elements of the de-aerator <NUM> may be formed as an integral unit / unitary structure. For example, the de-aerator <NUM> embodiment shown in <FIG> has a fluid inlet <NUM>, a body <NUM>, a vent tube <NUM>, a helical fluid passage <NUM>, a base panel <NUM>, partitions <NUM>, and a fluid collection body <NUM> formed as a unitary structure. Such a structure may be formed using additive manufacturing techniques, or 3D printing techniques, or the like. In some embodiments, portions of the de-aerator <NUM> (e.g., the fluid inlet <NUM>, body <NUM>, helical fluid passage <NUM>, partitions <NUM>, and base panel <NUM>) may be formed as a unitary structure that can be assembled with other elements to produce the de-aerator <NUM>.

While the principles of the disclosure have been described above in connection with specific apparatuses and methods, it is to be clearly understood that this description is made only by way of example and not as limitation on the scope of the disclosure.

The singular forms "a," "an," and "the" refer to one or more than one, unless the context clearly dictates otherwise. For example, the term "comprising a specimen" includes single or plural specimens and is considered equivalent to the phrase "comprising at least one specimen. " The term "or" refers to a single element of stated alternative elements or a combination of two or more elements unless the context clearly indicates otherwise. As used herein, "comprises" means "includes. " Thus, "comprising A or B," means "including A or B, or A and B," without excluding additional elements.

It is noted that various connections are set forth between elements in the present description and drawings (the contents of which are included in this disclosure by way of reference). It is noted that these connections are general and, unless specified otherwise, may be direct or indirect and that this specification is not intended to be limiting in this respect.

No element, component, or method step in the present disclosure is intended to be dedicated to the public regardless of whether the element, component, or method step is explicitly recited in the claims. As used herein, the terms "comprise", "comprising", or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus.

Claim 1:
A de-aerator (<NUM>) for an oil system (<NUM>) of a gas turbine engine (<NUM>), comprising:
a body (<NUM>) extending between a first axial end (<NUM>) and a second axial end (<NUM>) opposite the first axial end (<NUM>), the body (<NUM>) having at least one sidewall (<NUM>) that extends between the first axial end (<NUM>) and the second axial end (<NUM>), and a base panel (<NUM>) connected to the at least one sidewall (<NUM>) at the second axial end (<NUM>), wherein the base panel (<NUM>) and the at least one sidewall (<NUM>) define an internal cavity (<NUM>) of the body (<NUM>);
a cover panel (<NUM>) connected to the body (<NUM>) at the first axial end (<NUM>);
a fluid inlet (<NUM>) in communication with the body (<NUM>) at the first axial end (<NUM>), the fluid inlet (<NUM>) having an internal flow passage (<NUM>) configured to direct fluid tangentially into the internal cavity (<NUM>);
a helical fluid passage (<NUM>) disposed within the internal cavity (<NUM>) having an entry end (<NUM>) and an exit end (<NUM>), the entry end (<NUM>) disposed to receive fluid from the fluid inlet (<NUM>) , the helical fluid passage (<NUM>) having a plurality of circumferential turns that collectively axially descend toward the second axial end (<NUM>) of the body (<NUM>), wherein the circumferential turns each include one or more air passages disposed radially inward providing a gas path to a central region (<NUM>) disposed radially inside of the helical fluid passage (<NUM>);
at least one partition (<NUM>) disposed within the internal cavity (<NUM>) in a plane that is substantially perpendicular to a central axis (<NUM>) of the de-aerator (<NUM>), at or below the exit end of the helical fluid passage (<NUM>), and spaced above the base panel (<NUM>) of the de-aerator (<NUM>) wherein the at least one partition (<NUM>) has an upper surface (54U), a lower surface (<NUM>), a thickness (<NUM>) extending between the upper surface (54U) and the lower surface (<NUM>); and
at least one fluid outlet (<NUM>) disposed adjacent the base panel (<NUM>), the at least one fluid outlet (<NUM>) configured to permit liquid passage from the internal cavity (<NUM>) of the body (<NUM>) to outside the body (<NUM>),
characterised in that
the at least one partition (<NUM>) has a plurality of apertures (<NUM>) extending through the partition (<NUM>) between the upper surface (54U) and the lower surface (<NUM>).