Patent Description:
Rotational equipment typically includes one or more seal assemblies for sealing gaps between rotors and stators. A typical seal assembly includes a contact seal with a seal element such as a knife edge seal that engages a seal land. Such a contact seal can generate a significant quantity of heat that can reduce efficiency of the rotational equipment as well as subject other components of the rotational equipment to high temperatures and internal stresses. To accommodate these high temperatures and stresses, certain components of the rotational equipment may be constructed from specialty high temperature materials. However, these materials can significantly increase manufacturing and servicing costs as well as mass of the rotational equipment. While non-contact seals have been developed in an effort to reduce heat within rotational equipment, there is still room for improvement to provide an improved non-contact seal. In particular, there is room in the art for a non-contact seal with improved damping characteristics.

<CIT> discloses features of the preamble of claim <NUM>.

According to an aspect of the present invention, an assembly is provided for rotational equipment as claimed in claim <NUM>.

The rotational equipment assembly may also include a secondary seal assembly configured to seal a gap between the seal base and the seal shoes. The secondary seal assembly may be configured to axially engage and radially move along a seal land surface of the first seal shoe. The one or more apertures may be arranged axially between the high pressure end and the seal land surface of the first seal shoe.

The present invention, in any of its aspects, may include any one or more of the individual features disclosed above and/or below alone or in any combination thereof.

<FIG> illustrates an assembly <NUM> for rotational equipment with an axial centerline <NUM>, which centerline <NUM> may also be an axis of rotation (e.g., a rotational axis) for one or more components of the rotational equipment assembly <NUM>. An example of such rotational equipment is a gas turbine engine for an aircraft propulsion system, an exemplary embodiment of which is described below in further detail (e.g., see <FIG>). However, the rotational equipment assembly <NUM> of the present disclosure is not limited to such an aircraft or gas turbine engine application. The rotational equipment assembly <NUM>, for example, may alternatively be configured with rotational equipment such as an industrial gas turbine engine, a wind turbine, a water turbine or any other apparatus in which a seal is provided between a stationary structure and a rotating structure; e.g., a rotor.

The rotational equipment assembly <NUM> of <FIG> includes a stationary structure <NUM>, a rotating structure <NUM> and a seal assembly <NUM> such as, for example, an adapting non-contact seal assembly. The seal assembly <NUM> is mounted with the stationary structure <NUM> and configured to substantially seal an annular gap between the stationary structure <NUM> and the rotating structure <NUM> as described below in further detail.

The stationary structure <NUM> includes a seal carrier <NUM>. This seal carrier <NUM> may be a discrete, unitary annular body. Alternatively, the seal carrier <NUM> may be configured with another component / portion of the stationary structure <NUM>. The seal carrier <NUM> has a seal carrier inner surface <NUM>. This seal carrier inner surface <NUM> may be substantially cylindrical. The seal carrier inner surface <NUM> extends circumferentially about (e.g., completely around) and faces towards the axial centerline <NUM>. The seal carrier inner surface <NUM> at least partially forms a bore in the stationary structure <NUM>. This bore is sized to receive the seal assembly <NUM>, which seal assembly <NUM> may be fixedly attached to the seal carrier <NUM> by, for example, a press fit connection between the seal assembly <NUM> and the seal carrier inner surface <NUM>. The seal assembly <NUM>, of course, may also or alternatively be fixedly attached to the seal carrier <NUM> using one or more other techniques / devices.

The rotating structure <NUM> includes a rotating seal land <NUM>. This rotating seal land <NUM> may be a discrete, unitary annular body. For example, the rotating seal land <NUM> may be mounted to a shaft of the rotating structure <NUM>. Alternatively, the rotating seal land <NUM> may be configured with another component / portion of the rotating structure <NUM>. For example, the rotating seal land <NUM> may be an integral part of a shaft of the rotating structure <NUM>, or another component mounted to the shaft.

The rotating seal land <NUM> of <FIG> has an outer seal land surface <NUM>. This outer seal land surface <NUM> may be substantially cylindrical. The outer seal land surface <NUM> extends circumferentially about (e.g., completely around) and faces away from the axial centerline <NUM>. The outer seal land surface <NUM> is configured to face towards and may be axially aligned with the seal carrier inner surface <NUM>. While <FIG> illustrates the outer seal land surface <NUM> and the seal carrier inner surface <NUM> with approximately equal axial lengths along the axial centerline <NUM>, the outer seal land surface <NUM> may alternatively be longer or shorter than the seal carrier inner surface <NUM> in other embodiments.

The seal assembly <NUM> includes a primary seal device <NUM> and one or more secondary seal devices <NUM>. The seal assembly <NUM> also includes one or more additional components for positioning, supporting and/or mounting one or more of the seal devices with the stationary structure <NUM>. The seal assembly <NUM> of <FIG>, for example, includes a first ring structure <NUM> configured for positioning, supporting and/or mounting the secondary seal devices <NUM> relative to the primary seal device <NUM>. The one or more secondary seal devices <NUM> and the first ring structure <NUM> may collectively provide a secondary seal assembly <NUM>. The first ring structure <NUM> may also be configured for axially positioning and/or supporting an axial first side surface <NUM> of the primary seal device <NUM> relative to the stationary structure <NUM>.

The seal assembly <NUM> of <FIG> also includes a second ring structure <NUM> (e.g., a scalloped support ring / plate) configured for axially positioning and/or supporting an axial second side surface <NUM> of the primary seal device <NUM> relative to the stationary structure <NUM>. However, the second ring structure <NUM> may be omitted where, for example, the second side surface <NUM> of the primary seal device <NUM> is abutted against another component / portion of the stationary structure <NUM> (e.g., an annular or castellated shoulder) or otherwise axially positioned / secured with the stationary structure <NUM>; e.g., see <FIG>.

Referring to <FIG>, the primary seal device <NUM> is configured as an annular seal device such as, but not limited to, a non-contact hydrostatic seal device. The primary seal device <NUM> includes a seal base <NUM>, a plurality of seal shoes <NUM>, a plurality of spring elements <NUM> (see also <FIG> and <FIG>).

The seal base <NUM> may be configured as an annular full hoop body. The seal base <NUM> of <FIG> extends circumferentially about (e.g., completely around) the axial centerline <NUM>. The seal base <NUM> is configured to extend circumferentially around and thereby circumscribe and support the seal shoes <NUM> as well as the spring elements <NUM>. Referring to <FIG>, the seal base <NUM> extends axially along the axial centerline <NUM> and forms the first side surface <NUM> and the second side surface <NUM>. The seal base <NUM> extends radially between a seal base inner side <NUM> and a seal base outer side <NUM>. The seal base outer side <NUM> radially engages (e.g., is press fit against or otherwise contacts) the stationary structure <NUM> and its inner surface <NUM> as shown in <FIG>.

Referring to <FIG>, the seal shoes <NUM> may be configured as arcuate bodies and are arranged circumferentially around the axial centerline <NUM> in an annular array. Each seal shoe <NUM>, for example, is arranged circumferentially between and next to a pair of adjacent circumferentially neighboring seal shoes <NUM>. The annular array of the seal shoes <NUM> extends circumferentially about (e.g., completely around) the axial centerline <NUM>, thereby forming an inner bore at an inner side <NUM> of the primary seal device <NUM>. As best seen in <FIG>, the inner bore is sized to receive the rotating seal land <NUM>, where the rotating structure <NUM> projects axially through (or into) the inner bore formed by the seal shoes <NUM>.

Referring to <FIG>, each of the seal shoes <NUM> extends radially from the inner side <NUM> of the primary seal device <NUM> to an outer side <NUM> of that seal shoe <NUM>. Each of the seal shoes <NUM> extends circumferentially about the axial centerline <NUM> between opposing circumferential first and second ends <NUM> and <NUM> of that seal shoe <NUM>. Referring to <FIG>, each of the seal shoes <NUM> extends axially along the axial centerline <NUM> between an axial first (e.g., upstream and/or high pressure) end <NUM> and an axial second (e.g., downstream and/or low pressure) end <NUM> of the seal shoe <NUM>. The axial seal shoe first end <NUM> may be an upstream and/or high pressure end relative, for example, to flow of leakage fluid across the primary seal device <NUM>. The axial seal shoe first end <NUM> is axially offset / displaced from the axial first side surface <NUM>. The axial seal shoe second end <NUM> may be a downstream and/or low pressure end relative, for example, to the flow of leakage fluid across the primary seal device <NUM>. The axial seal shoe second end <NUM> may be axially aligned with the axial second side surface <NUM>. The seal shoes <NUM> of the present disclosure, however, are not limited to such exemplary relationships.

Each of the seal shoes <NUM> includes a seal shoe base <NUM> and one or more seal shoe projections 74A-D (generally referred to as "<NUM>") (e.g., inner projections such as rails and/or teeth). Each seal shoe <NUM> of <FIG> also includes a (e.g., non-rotating) seal land <NUM> (e.g., a secondary seal, seal land) for the one or more secondary seal devices <NUM> (see <FIG>).

The seal shoe base <NUM> of <FIG> and <FIG> includes one or more (e.g., arcuate) base outer surfaces 78A-B (generally referred to as "<NUM>") and one or more (e.g., arcuate) base inner surfaces 80A-E (generally referred to as "<NUM>"). The seal shoe base <NUM> extends radially between the one or more base outer surfaces <NUM> and the one or more base inner surfaces <NUM>. Referring to <FIG>, the seal shoe base <NUM> extends circumferentially about the axial centerline <NUM> between the circumferential seal shoe first end <NUM> and the circumferential seal shoe second end <NUM>. The seal shoe base <NUM> includes a first end surface at the circumferential seal shoe first end <NUM> and a second end surface at the circumferential seal shoe second end <NUM>. Each of the end surfaces may be a flat planar surface. Each of the end surfaces, for example, may have a straight sectional geometry when viewed, for example, in a plane perpendicular to the axial centerline <NUM>; e.g., the plane of <FIG>. Referring to <FIG>, the seal shoe base <NUM> extends axially between the axial seal shoe first end <NUM> and the axial seal shoe second end <NUM>.

The seal shoe projections <NUM> are arranged at discrete axial locations along the axial centerline <NUM> and the seal shoe base <NUM>. Each pair of axially adjacent / neighboring projections <NUM> may thereby be axially separated by an (e.g., arcuate) inter-projection gap. The seal shoe projections <NUM> of <FIG> are configured parallel to one another.

The seal shoe projections <NUM> may be arranged in a concentrated grouping <NUM>. This grouping <NUM> may be asymmetrically arranged axially along the centerline <NUM> between the axial seal shoe first end <NUM> and the axial seal shoe second end <NUM>. For example, an axial center <NUM> (e.g., midpoint) of the grouping <NUM> of the seal shoe projections <NUM> in <FIG> is arranged closer to the axial seal shoe first end <NUM> than the axial seal shoe second end <NUM>. The seal shoe projections <NUM> of the present disclosure, however, are not limited to the foregoing exemplary asymmetric configuration. For example, the axial center <NUM> of the grouping <NUM> of the seal shoe projections <NUM> may alternatively be arranged closer to the axial seal shoe second end <NUM> than the axial seal shoe first end <NUM>, or still alternatively positioned midway between the axial seal shoe first end <NUM> and the axial seal shoe second end <NUM>.

The seal shoe projections <NUM> are connected to (e.g., formed integral with or otherwise attached to) the seal shoe base <NUM>. Each of the seal shoe projections <NUM> projects radially inwards from the seal shoe base <NUM> and its base inner surfaces <NUM> to an unsupported distal projection end.

Each of the seal shoe projections <NUM> has a projection inner surface 86A-D (generally referred to as "<NUM>") at its unsupported distal projection end. One or more or each of the projection inner surfaces <NUM> may also be at (e.g., on, adjacent or proximate) the inner side <NUM> of the primary seal device <NUM>. Each projection inner surface <NUM> may be an arcuate surface. Each projection inner surface <NUM>, for example, may have an arcuate sectional geometry when viewed, for example, in a plane perpendicular to the axial centerline <NUM>; e.g., the plane of <FIG>. The projection inner surfaces <NUM> are configured to be arranged in close proximity with (but not touch) and thereby sealingly mate with the outer seal land surface <NUM> in a non-contact manner (see <FIG>), where the rotating structure <NUM> projects axially through (or into) the inner bore formed by the seal shoes <NUM>.

Each of the seal shoe projections <NUM> extends axially between opposing projection end surfaces (e.g., <NUM> and <NUM>). Each of these end surfaces extends radially between and may be contiguous with a respective one of the projection inner surfaces (e.g., 86D in <FIG>) and a respective one of the base inner surfaces (e.g., 80A and 80B in <FIG>).

Each of the seal shoe projections <NUM> of <FIG> has the same radial height. In other embodiments, however, one or more of the seal shoe projections <NUM> may have a different radial height than at least another one of the seal shoe projections <NUM>; e.g., see <FIG>.

Referring to <FIG>, the seal land <NUM> extends circumferentially to and between the circumferential seal shoe sides <NUM> and <NUM>. Referring now to <FIG>, the seal land <NUM> projects radially out from the seal shoe base <NUM> to an unsupported distal seal land end <NUM> at (e.g., on, adjacent or proximate) the seal shoe outer side <NUM>. The seal land <NUM> extends axially between opposing (e.g., arcuate) first and second side surfaces <NUM> and <NUM>. The first side surface <NUM> is configured as a seal land surface for the one or more secondary seal devices <NUM> as shown in <FIG>. More particularly, when the seal shoes <NUM> are arranged in the array, the first side surfaces <NUM> collectively form a generally annular, but circumferentially segmented, side surface configured for sealingly engaging with (e.g., contacting) the secondary seal devices <NUM> as shown in <FIG>. The seal shoes <NUM> of the present disclosure, however, are not limited to the foregoing exemplary configuration.

The seal land <NUM> may be generally axially aligned with and/or axially overlapped by the one or more seal shoe projections <NUM>. The seal land <NUM> of <FIG>, for example, is axially aligned with and is axially overlapped by the seal shoe projection 74B. The present disclosure, however, is not limited to such an exemplary arrangement. For example, in other embodiments, the seal land <NUM> may be axially aligned with any other one of the seal shoe projections (e.g., 74A, 74C and/or 74D). In still other embodiments, the seal land <NUM> may be axially offset from the seal shoe projections <NUM>. The seal land <NUM>, for example, may be arranged axially upstream of (e.g., towards the end <NUM>) or axially downstream of (e.g., towards the end <NUM>) the one or more seal shoe projections <NUM> / grouping <NUM>. In another example, the seal land <NUM> may be arranged axially between an adjacent / neighboring pair of seal shoe projections <NUM> (e.g., 74A and 74B, 74B and 74C, 74C and 74D).

The seal shoe <NUM> of <FIG> is configured with an axial first end portion <NUM>, an axial intermediate portion <NUM> and an axial second end portion <NUM>. The first end portion <NUM> is disposed at the axial seal shoe first end <NUM>. The first end portion <NUM> of <FIG>, for example, projects axially along the axial centerline <NUM> out from the intermediate portion <NUM> to the axial seal shoe first end <NUM>. The intermediate portion <NUM> extends axially along the axial centerline <NUM> between (e.g., and to) the first and the second end portions <NUM> and <NUM>. The intermediate portion <NUM> of <FIG> is configured with the one or more seal shoe projections <NUM> as well as the seal land <NUM>. The second end portion <NUM> is disposed at the axial seal shoe second end <NUM>. The second end portion <NUM> of <FIG>, for example, projects axially along the axial centerline <NUM> out from the intermediate portion <NUM> to the axial seal shoe second end <NUM>.

As best seen in <FIG>, the first end portion <NUM> is cantilevered from the intermediate portion <NUM>. Thus, other than through the intermediate portion <NUM>, the first end portion <NUM> is otherwise unsupported by another element and/or device. By contrast, as generally shown in <FIG> and <FIG> and described below in further detail, the intermediate portion <NUM> and/or the second end portion <NUM> are each supported by a respective one of the spring elements <NUM>.

Referring to <FIG>, the spring elements <NUM> are arranged circumferentially about the axial centerline <NUM> in an annular array. Referring to <FIG> and <FIG>, the spring elements <NUM> are also arranged (e.g., radially) between the seal shoes <NUM> and the seal base <NUM>. Each of the spring elements <NUM> is configured to moveably and resiliently connect a respective one of the seal shoes <NUM> to the seal base <NUM>.

The spring element <NUM> of <FIG> includes first and second mounts <NUM> and <NUM> (e.g., inner and outer radial fingers / projections) and one or more spring beams 110A and 110B (generally referred to as "<NUM>"). The first mount <NUM> may be directly or indirectly connected to (e.g., formed integral with or otherwise attached to) a respective one of the seal shoes <NUM> and each of its portions <NUM> and/or <NUM> at (e.g., on, adjacent or proximate) the circumferential seal shoe first end <NUM>, where the opposing circumferential seal shoe second end <NUM> is free floating (e.g., the seal shoe <NUM> is cantilevered from the first mount <NUM>). The first mount <NUM> projects radially outward from the seal shoe base <NUM> and each of its portions <NUM> and/or <NUM>.

The second mount <NUM> may be directly or indirectly connected to the seal base <NUM>, and is generally circumferentially aligned with or near the circumferential seal shoe second end <NUM>. The second mount <NUM> is therefore disposed a circumferential distance from the first mount <NUM>. The second mount <NUM> projects radially inward from the seal base <NUM>.

The spring beams <NUM> are configured as resilient, biasing members of the primary seal device <NUM>. The spring beams <NUM> of <FIG>, for example, are configured as cantilevered-leaf springs. These spring beams <NUM> may be radially stacked and spaced apart from one another so as to form a four bar linkage with the first mount <NUM> and the second mount <NUM>. More particularly, each of the spring beams <NUM> may be directly or indirectly connected to the first mount <NUM> and the second mount <NUM>. Each of the spring beams <NUM> extends laterally (e.g., circumferentially or tangentially) between and to the first mount <NUM> and the second mount <NUM>. The spring beams <NUM> of <FIG> may thereby laterally overlap a major circumferential portion (e.g., ~<NUM>-<NUM>%) of the respective seal shoe <NUM>.

During operation of the primary seal device <NUM> of <FIG>, rotation of the rotating structure <NUM> may develop aerodynamic forces and apply a fluid pressure to the seal shoes <NUM> causing each seal shoe <NUM> to respectively move radially up and down relative to the outer seal land surface <NUM>. The fluid velocity may increase as a gap between a respective seal shoe <NUM> and the outer seal land surface <NUM> increases, thus reducing pressure in the gap and drawing the seal shoe <NUM> radially inwardly toward the outer seal land surface <NUM>. As the gap closes, the velocity may decrease and the pressure may increase within the gap, thus, forcing the seal shoe <NUM> radially outwardly from the outer seal land surface <NUM>. The respective spring element <NUM> and its spring beams <NUM> may deflect and move with the seal shoe <NUM> to enable provision of a primary seal of the gap between the outer seal land surface <NUM> and seal shoe projections <NUM> within predetermined design tolerances.

To regulate and/or reduce vibratory up and down movement of the seal shoes <NUM>, the first end portion <NUM> of each seal shoe <NUM> may be elongated in an axial direction away from the respective spring element <NUM>. For example, by increasing surface area (e.g., area of surface 78B) of the seal shoe <NUM> at (e.g., on, adjacent or proximate) the axial seal shoe first end <NUM> where the fluid pressure is the greatest, the interaction between motion of the seal shoe <NUM> and time-varying pressures acting upon the seal shoe <NUM> may be more favorably aligned to provide improved seal shoe damping; e.g., positive seal shoe damping. More particularly, by increasing surface area of the first end portion <NUM>, the relatively high pressure fluid (e.g., compressed gas) in a plenum <NUM> upstream of the seal assembly <NUM> and adjacent the first end portion <NUM> has larger surface(s) on which to act.

While the primary seal device <NUM> described above is operable to generally seal the annular gap between the stationary structure <NUM> and the rotating structure <NUM>, the fluid (e.g., gas) may still flow axially through passages 114A-C (generally referred to as "<NUM>") defined by radial air gaps between the elements <NUM>, <NUM> and <NUM>. The secondary seal assembly <NUM> and its one or more secondary seal devices <NUM> therefore are provided to seal off these passages <NUM> and, thereby, further and more completely seal the annular gap.

Each of the secondary seal devices <NUM> may be configured as a ring seal element such as, but not limited to, a split ring. Alternatively, one or more of the secondary seal devices <NUM> may be configured as a full hoop body ring, an annular brush seal or any other suitable ring-type seal.

The secondary seal devices <NUM> of <FIG> are arranged together in an axial stack. In this stack, each of the secondary seal devices <NUM> axially engages (e.g., contacts) another adjacent one of the secondary seal devices <NUM>. The stack of the secondary seal devices <NUM> is arranged with the first ring structure <NUM>, which positions and mounts the secondary seal devices <NUM> with the stationary structure <NUM> adjacent the primary seal device <NUM>. In this arrangement, the stack of the secondary seal devices <NUM> is operable to axially engage (e.g., contact) and form a seal between one or more or each of the first side surfaces <NUM> of the seal shoes <NUM> and an annular surface <NUM> of the first ring structure <NUM>. These surfaces <NUM> and <NUM> are axially aligned with one another, which enables the stack of the secondary seal devices <NUM> to slide radially against, but maintain a seal engagement with, one or more or each of the seal lands <NUM> and their side surfaces <NUM> as the seal shoes <NUM> move radially relative to the outer seal land surface <NUM> as described above.

The first ring structure <NUM> may include a secondary seal device support ring <NUM> and a retention ring <NUM>. The support ring <NUM> is configured with an annular full hoop body, which extends circumferentially around the axial centerline <NUM>. The support ring <NUM> includes the annular surface <NUM>, and is disposed axially adjacent and engaged with (e.g., axially contacts, abutted against) the seal base <NUM>.

The retention ring <NUM> is configured with an annular full hoop body, which extends circumferentially around the axial centerline <NUM>. The retention ring <NUM> is disposed axially adjacent and is engaged with (e.g., axially contacts, abutted against) the support ring <NUM>, thereby capturing the stack of the secondary seal devices <NUM> within an annular channel <NUM> formed between the rings <NUM> and <NUM>. The stack of the secondary seal devices <NUM>, of course, may also or alternatively be attached to one of the rings by, for example, a press fit connection and/or otherwise.

In some embodiments, the first end portion <NUM> of one or more or each seal shoe <NUM> projects axially along the axial centerline <NUM>, in the direction away from the respective spring element <NUM>, along and/or beyond (e.g., an entirety of) the secondary seal assembly <NUM>. For example, the first end portion <NUM> may project axially past the one or more secondary seal devices <NUM> and/or the first ring structure <NUM> and/or one or more of the first ring structure elements <NUM> and <NUM>. With this arrangement, the axial seal shoe first end <NUM> is axially offset / displaced from the secondary seal assembly <NUM> and its axially closest surface (e.g., surface <NUM>) by a non-zero axial distance <NUM>.

In some embodiments, referring to <FIG>, the first end portion <NUM> of one or more or each of the seal shoes <NUM> may be configured with one or more tuning features <NUM> adapted to influence dynamic motion of that respective seal shoe <NUM>. Each feature <NUM> may influence the dynamic motion of the respective seal shoe <NUM> by tuning damping provided by the first end portion <NUM> for the seal shoe <NUM>. One or more or each of the features <NUM>, for example, may be configured as a protrusion that increases the mass and/or exposed surface area of the first end portion <NUM>. One or more or each of the features <NUM> may also or alternatively be configured as an aperture (e.g., a through-hole, a channel, a notch, a recession, etc.) that decreases the mass and/or exposed surface area of the first end portion <NUM>.

Referring to <FIG>, the first end portion <NUM> is configured with one or more circumferentially extending ribs <NUM>. Each of these ribs <NUM> extends circumferentially between (e.g., and to) the circumferential seal shoe ends <NUM> and <NUM> (see <FIG>). Each of the ribs <NUM> may be an outer rib as shown in <FIG>. More particularly, each of the ribs <NUM> may project radially out from the seal shoe base <NUM>, in a radial outward direction away from the axial centerline <NUM>, to a respective unsupported distal rib end <NUM>. However, in other embodiments, at least one (or more or each) of the ribs <NUM> (e.g., inner ribs) may project radially out from the seal shoe base <NUM>, in a radial inward direction towards the axial centerline <NUM>, to its respective unsupported distal rib end <NUM> as shown, for example, in <FIG> and <FIG>.

In some embodiments, referring to <FIG>, the ribs <NUM> may be arranged at discrete locations along the axial centerline <NUM> and the seal shoe base <NUM>. However, in other embodiments, a plurality of the ribs <NUM> may be axially aligned as shown, for example, in <FIG>. In the embodiments of <FIG> and <FIG>, each rib <NUM> is located at the axial seal shoe first end <NUM>. Of course, in other embodiments, each rib <NUM> may be axially displaced from the axial seal shoe first end <NUM> by a non-zero distance.

Referring to <FIG>, the first end portion <NUM> may alternatively (or also) be configured with one or more axially extending ribs <NUM>. Each of these ribs <NUM> extends axially between (e.g., and to) the axial seal shoe first end <NUM> and the first side surface <NUM>. Each of the ribs <NUM> may be an outer rib as shown in <FIG>. More particularly, each of the ribs <NUM> may project radially out from the seal shoe base <NUM>, in the radial outward direction away from the axial centerline <NUM>, to a respective unsupported distal rib end <NUM>. However, in other embodiments, one or more or each of the ribs <NUM> (e.g., inner ribs) may project radially out from the seal shoe base <NUM>, in the radial inward direction towards the axial centerline <NUM>, to its respective unsupported distal rib end <NUM> (not shown).

In some embodiments, referring to <FIG>, the ribs <NUM> may be arranged at discrete locations circumferentially about the axial centerline <NUM> and the seal shoe base <NUM>. The present disclosure, however, is not limited to such an exemplary arrangement. For example, in other embodiments, the ribs <NUM> may be aligned as generally described with the ribs <NUM> in <FIG>.

Referring to <FIG>, the first end portion <NUM> is configured with one or more apertures <NUM>; e.g., a through-hole, a channel, a notch, a recession, etc. One or more or each of these apertures <NUM> extend radially through the seal shoe base <NUM> between and to the opposing surfaces (e.g., 78B and 80E). One or more or each of the apertures <NUM> extend axially within (or alternatively partially into) the seal shoe base <NUM>. One or more or each of the apertures <NUM> may also or alternatively extend circumferentially within (or alternatively partially into or through) the seal shoe base <NUM>. While each of the apertures <NUM> is shown as extending completely radially through the first end portion <NUM> and the seal shoe base <NUM>, one or more or each of the apertures <NUM> may alternatively extend partially radially into the first end portion <NUM> and the seal shoe base <NUM> from the surface (e.g., 78B or 80E).

In some embodiments, referring to <FIG>, the apertures <NUM> may be arranged at discrete locations circumferentially about the axial centerline <NUM> and the seal shoe base <NUM>. The present disclosure, however, is not limited to such an exemplary arrangement. For example, in other embodiments, the apertures <NUM> may also or alternatively be axially displaced, etc..

In some embodiments, the first end portion <NUM> may be configured with various different types of the features <NUM>. For example, the first end portion <NUM> may be configured a combination of any two or more of the features <NUM>, <NUM> and/or <NUM> described above. Of course, in still other embodiments, the first end portion <NUM> may also or alternatively be configured with one or more other types of features <NUM>.

In some embodiments, as best seen in <FIG> and <FIG>, the primary seal device <NUM> and some or all of its elements (e.g., <NUM>-<NUM>) may be configured as a monolithic body. However, the present disclosure is not limited to such a primary seal device construction.

As described above, the rotational equipment assembly <NUM> of the present disclosure may be configured with various different types and configurations of rotational equipment. <FIG> illustrates one such type and configuration of the rotational equipment - a geared turbofan gas turbine engine <NUM>. Such a turbine engine includes various stationary structures (e.g., bearing supports, hubs, cases, etc.) as well as various rotors (e.g., rotor disks, shafts, shaft assemblies, etc.) as described below, where the stationary structure <NUM> and the rotating structure <NUM> can respectively be configured as anyone of the foregoing structures in the turbine engine <NUM> of <FIG>, or other structures not mentioned herein.

The turbine engine <NUM> of <FIG> extends along the axial centerline <NUM> between an upstream airflow inlet <NUM> and a downstream airflow exhaust <NUM>. The turbine engine <NUM> includes a fan section <NUM>, a compressor section <NUM>, a combustor section <NUM> and a turbine section <NUM>. The compressor section <NUM> includes a low pressure compressor (LPC) section 143A and a high pressure compressor (HPC) section 143B. The turbine section <NUM> includes a high pressure turbine (HPT) section 145A and a low pressure turbine (LPT) section 145B.

The engine sections <NUM>-145B are arranged sequentially along the axial centerline <NUM> within an engine housing <NUM>. This engine housing <NUM> includes an inner case <NUM> (e.g., a core case) and an outer case <NUM> (e.g., a fan case). The inner case <NUM> may house one or more of the engine sections 143A-145B; e.g., an engine core. The outer case <NUM> may house at least the fan section <NUM>.

Each of the engine sections <NUM>, 143A, 143B, 145A and 145B includes a respective rotor <NUM>-<NUM>. Each of these rotors <NUM>-<NUM> includes a plurality of rotor blades arranged circumferentially around and connected to one or more respective rotor disks. The rotor blades, for example, may be formed integral with or mechanically fastened, welded, brazed, adhered and/or otherwise attached to the respective rotor disk(s).

The fan rotor <NUM> is connected to a gear train <NUM>, for example, through a fan shaft <NUM>. The gear train <NUM> and the LPC rotor <NUM> are connected to and driven by the LPT rotor <NUM> through a low speed shaft <NUM>. The HPC rotor <NUM> is connected to and driven by the HPT rotor <NUM> through a high speed shaft <NUM>. The shafts <NUM>-<NUM> are rotatably supported by a plurality of bearings <NUM>. Each of these bearings <NUM> is connected to the engine housing <NUM> by at least one stationary structure such as, for example, an annular support strut.

During operation, air enters the turbine engine <NUM> through the airflow inlet <NUM>. This air is directed through the fan section <NUM> and into a core gas path <NUM> and a bypass gas path <NUM>. The core gas path <NUM> extends sequentially through the engine sections 143A-145B. The air within the core gas path <NUM> may be referred to as "core air". The bypass gas path <NUM> extends through a bypass duct, which bypasses the engine core. The air within the bypass gas path <NUM> may be referred to as "bypass air".

The rotational equipment assembly <NUM> may be included in various turbine engines other than the one described above as well as in other types of rotational equipment. The rotational equipment assembly <NUM>, for example, may be included in a geared turbine engine where a gear train connects one or more shafts to one or more rotors in a fan section, a compressor section and/or any other engine section. Alternatively, the rotational equipment assembly <NUM> may be included in a turbine engine configured without a gear train. The rotational equipment assembly <NUM> may be included in a geared or non-geared turbine engine configured with a single spool, with two spools (e.g., see <FIG>), or with more than two spools. The turbine engine may be configured as a turbofan engine, a turbojet engine, a propfan engine, a pusher fan engine or any other type of turbine engine. The present disclosure therefore is not limited to any particular types or configurations of turbine engines or rotational equipment.

Claim 1:
An assembly for rotational equipment, comprising:
a plurality of seal shoes (<NUM>) arranged circumferentially around an axial centerline (<NUM>), the plurality of seal shoes (<NUM>) comprising a first seal shoe (<NUM>) that includes
a seal shoe base (<NUM>) extending axially along the axial centerline (<NUM>) between a high pressure end (<NUM>) and a low pressure end (<NUM>), and
one or more inner projections (74A, 74B, 74C, 74D) extending radially out from the seal shoe base (<NUM>) in an inward direction towards the axial centerline (<NUM>);
a seal base (<NUM>) circumscribing the annular array; and
a plurality of spring elements (<NUM>) comprising a first spring element (<NUM>), the first spring element (<NUM>) including a first mount (<NUM>), a second mount (<NUM>) and a spring beam (<NUM>), the first mount (<NUM>) projecting out from the first seal shoe (<NUM>), the second mount (<NUM>) projecting out from the seal base (<NUM>), and the spring beam (<NUM>) extending laterally between and connected to the first mount (<NUM>) and the second mount (<NUM>);
characterised in that the first seal shoe (<NUM>) includes one or more apertures (<NUM>) extending radially through the seal shoe base (<NUM>), wherein the one or more apertures (<NUM>) are arranged axially between the high pressure end (<NUM>) and the first spring element (<NUM>).