EP1908929A2

EP1908929A2 - Lubricant tank with a filler port for a gas turbine engine, and corresponding gas turbine engine

Info

Publication number: EP1908929A2
Application number: EP20070253639
Authority: EP
Inventors: Francis Bonacorsi
Original assignee: Pratt and Whitney Canada Corp
Current assignee: Pratt and Whitney Canada Corp
Priority date: 2006-09-14
Filing date: 2007-09-13
Publication date: 2008-04-09
Also published as: WO2008031195A1

Abstract

A gas turbine engine oil tank (31) with an opening (34) adapted to receive an oil filler housing (40), the oil filler housing (40) preferably comprising an oil filler port (43), a shut-off valve (45) and an oil level indicator (50).

Description

TECHNICAL FIELD

The invention relates generally to gas turbine engines and, more particularly, to design and assembly of gas turbine engines.

BACKGROUND OF THE ART

Aero-engines used in multi-engine aircraft typically have right and left installations, that is one or more engines are installed on the right side of the aircraft, and the other(s) on the other side. This often requires the engine to have right-and left-hand configurations, so that equipment is accessible to service personnel, or properly position to interface with aircraft systems, etc. For example, an oil tank filler neck, cap and sight glass for viewing the oil level must be accessible for using and maintaining the engine lubrication system. Thus, the engine oil tank housing normally features two oil filler ports and two oil-indicating pads, one on each side of the housing to provide accessibility for either left or right engine configurations). The filler cap, shut-off valve, oil indicator and overfill valve are installed are separately mounted to the oil tank only on one side of the engine (e.g. the right side for a right-hand installation), with plugs or blanks installed in the unused holes provided on the opposite side of the housing (e.g. the left side of a right-hand installed engine). Installation is thus complex and time-consuming, thus increasing both assembly and maintenance costs as well as increasing the potential for installation errors.
Accordingly, there is a need to provide an improved approach that overcomes at least one of the deficiencies of the prior art.

SUMMARY OF THE INVENTION

It is therefore an object of this invention to provide an access housing for use with a gas turbine engine.
In one preferred arrangement described herein, the present invention provides a gas turbine engine including a compressor and a turbine mounted on bearings to an axial shaft, the compressor having an impeller for pressurizing air in the engine, and a combustion section in fluid communication with pressurized air from the compressor. The gas turbine engine also includes a lubrication system disposed within the engine for lubricating the bearings, the lubrication system having an oil tank mounted within the engine for storing oil, the oil tank being disposed within an oil tank housing having an opening adapted to receive an oil filler housing, the oil filler housing comprising an oil filler port, a shut-off valve and an oil level indicator.
In another preferred arrangement described herein, the present invention provides an oil filler housing for enabling rapid installation of oil tank components to an oil tank housing that stores oil for a lubrication system of a gas turbine engine. The oil filler housing includes an oil filler port for adding oil to an oil tank within the oil tank housing of the engine, a shut-off valve for preventing oil from escaping when the removable cap is removed, and an oil level indicator for visually indicating an oil level in the oil tank.
In another aspect, the present invention provides a method of mounting an oil filler housing to an oil tank housing of a gas turbine engine. The method includes steps of aligning the oil filler housing with a corresponding opening in the oil tank housing where the oil filler housing has an oil filler port for adding oil to an oil tank within the oil tank housing of the engine, a shut-off valve for preventing oil from escaping when a removable cap is removed from the filler port, and an oil level indicator for visually indicating an oil level in the oil tank. The method also includes the step of securing the oil filler housing to the oil tank housing.
In another aspect, the invention provides a filler housing for a gas turbine engine, the filler housing comprising: a single housing including a filler port for adding a fluid to a fluid tank of the engine and at least one of a shut-off valve for preventing fluid from escaping when a removable cap is removed, a fluid level indicator, a filler cap, and an overfill valve, the filler housing adapted for direct mounting in an opening provided in a fluid reservoir of the gas turbine engine.
Further details of these and other aspects of the present invention will be apparent from the detailed description and figures included below.

DESCRIPTION OF THE DRAWINGS

Reference is now made to the accompanying figures depicting aspects of the present invention, in which:

Figure 1 is a schematic cross-sectional view of a turbofan gas turbine engine as an example illustrating an application of the present invention;
Figure 2 is an isometric perspective view of an oil tank housing having an opening over which an oil filler housing is to be mounted in accordance with an embodiment of the present invention;
Figure 3 is an isometric perspective view of an oil tank housing to which a blank or plug is mounted;
Figure 4 is an isometric perspective view of the the oil tank housing, similar to Figure 3, showing the oil filler housing mounted to the oil tank housing;
Figure 5 is a front elevation view of the oil filler housing; and
Figure 6 is a rear isometric perspective view of the oil filler housing.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring to Figure 1, a turbofan gas turbine engine incorporating an embodiment of the present invention is presented as an example of the application of the present invention, and includes a housing 10, a core casing 13, a low pressure spool assembly seen generally at 12 which includes a shaft 15 interconnecting a fan assembly 14, a low pressure compressor 16 and a low pressure turbine assembly 18, and a high pressure spool assembly seen generally at 20 which includes a shaft at 25 interconnecting a high pressure compressor assembly 22 and a high pressure turbine assembly 24. The core casing 13 surrounds the low and high pressure spool assemblies 12 and 20 in order to define a main fluid path (not indicated) therethrough. In the main fluid path there are provided a combustion section 26 having a combustor 28 therein. Pressurized air provided by the high pressure compressor assembly 22 through a diffuser 30 enters the combustion section 26 for combustion taking place in the combustor 28. An accessory gearbox (unindicated) including a oil tank housing 31 is mounted to a lower part of the engine casing.
A plurality of bearings (not illustrated) are mounted to the shaft 15 to rotationally support the low-pressure and high-pressure compressor and turbine assemblies. These bearings are lubricated and cooled by oil circulated by an engine lubrication system (or "oil system") disposed within the engine. The engine-lubrication system typically includes pumps (both pressure and scavenge pumps), an oil filter, a heat-exchanger, oil-distribution lines and an oil tank disposed within an oil tank housing.
Figures 2-4 show an oil tank housing 31 for use with a lubrication system of a gas turbine engine. The oil tank housing 31 has a rear access cavity 32 on a rear face of the housing for connection to other components of the lubrication system. The oil tank housing 31 also includes an opening 34 on each side of the housing 31 for receiving an oil filler housing 40 (as shown in Figure 4) or a correspondingly shaped blank or plug. In other words, the oil filler housing 40 is mounted to the oil tank housing 31 so as to cover, or close off, the opening 34.
Openings 34 are provided on both sides of the oil tank housing 31 for dual-engine applications, i.e. so that the oil tank housing 31 can be configured for either left-hand or right-hand engine configurations. Depending on the configuration (left or right engine), one of the two openings will receive the oil filler housing 40 while the opposite one (the unused side) will receive a blank or plug.
Although the openings 34 are shown as generally circular, the openings can be of another shape although the shape should be one that is easy to manufacture and which provides access to the interior of the tank housing. The single large opening 34 on each side of the oil tank housing 30 provides ample access to the interior of the oil tank housing for casting cleaning, casting repairs and/or inspections for the casting maker.
As shown in Figures 2-3, each opening 34 is surrounded by a generally non-circular lip 36 having three tapped bores 38 for threadedly engaging threaded fasteners (not shown), although the number of bores and their locations can of course be varied. The threaded fasteners are used to threadedly secure the oil filler housing 40 to the lip 36 of the oil tank housing 30. To mount the oil filler housing 40 to the oil tank housing 30, the oil filler housing 40 is aligned with the opening 34 of the oil tank housing 30 such that three bores 41 in a peripheral flange 42 of the oil filler housing align with the tapped bores 38 of the lip 36 of the oil tank housing 30. In addition, the non-circular lip 36 corresponds in shape to the oil filler housing so as to facilitate relative alignment of these two components. The threaded fasteners are then inserted through the bores 41 in the peripheral flange 42 of the oil filler housing 40 and threaded snugly into the tapped bores of the oil tank housing 30.
Figures 5-6 shows the oil filler housing 40 in accordance with an embodiment of the present invention. The oil filler housing 40 includes an oil filler port 43 (preferably having a removable cap 44) for adding oil to an oil tank within the oil tank housing of the engine. The oil filler housing 40 also includes a shut-off valve 45 for preventing oil from escaping when the removable cap is removed. The oil filler housing 40 further includes an oil level indicator 50 for visually indicating an oil level in the oil tank. The oil level indicator 50 includes a sight glass 52 for viewing the oil level. The sight glass has a maximum fill line (a "max" line) 54 as well as a minimum fill line (a "min" line) 56.
As shown in Figures 5-6, the oil filler housing 40 can optionally include an anchor point 46 for receiving a flexible tether 48 for tethering the removable filler cap 44 to the oil filler housing 40. The tether prevents ground crew from losing or dropping the cap when the cap has been unscrewed or otherwise removed from the filler port (i.e. when adding oil to the engine). The tether 48 can be a chain, a cord, or a thin flexible nylon or plastic cable.
Because the oil filler housing 40 is a single "modular" unit, it simplifies assembly and maintenance of the engine and also reduces the likelihood of installation errors occurring. In other words, by combining the filler port, oil level indicator and shut-off valve in one integral housing as a single unit, installation and dismantling times (and costs) are reduced.
As shown in Figure 5, the oil filler housing 40 is constructed such that a top of the oil filler port 43 is higher than the max oil line 52 of the oil level indicator 50, which thus eliminates the need for an overfill valve. Elimination of the overfill valve provides both cost and weight savings for the engine.
As will be appreciated, the exact types of oil level indicator, shut-off valve and filler port can be varied. The oil filler housing described and illustrated herein represents the best mode of implementing the invention known to the inventors, and therefore it will be appreciated that minor variations, improvements, refinements and substitutions may be made without departing from the invention, including modifying or substituting other types of filler ports, shut-off valves or oil indicators.
The above description is meant to be exemplary only, and one skilled in the art will recognize that changes may be made to the embodiments described without departing from the scope of the invention disclosed. For example, application of the present concept is not limited to an oil filler housing, but rather to any housing required for access on a gas turbine engine and for which placement is affect by the left- or right-handedness of installalation on an aircraft. The access housing can be used not only for turbofans or turbojets, but also for turboprops, turboshafts or any other gas turbine engine. Still other modifications which fall within the scope of the present invention will be apparent to those skilled in the art, in light of a review of this disclosure, and such modifications are intended to fall within the appended claims.

Claims

A gas turbine engine comprising an oil tank mounted to the engine for storing oil, the oil tank having an opening (34) adapted to receive an oil filler housing (40), the oil filler housing (40) comprising at least an oil filler port (43), a shut-off valve (45) and an oil level indicator (50).
The gas turbine engine as defined in claim 1, wherein a top of the filler port (43) is higher than a maximum fill line of the oil level indicator (50) when the oil filler housing (40) is mounted to the oil tank housing (31).
The gas turbine engine as defined in claim 1 or 2, wherein the oil filler housing (40) further comprises an anchor point (46) for receiving a flexible tether (48) for tethering a removable filler cap (44) to the oil filler housing (40).
The gas turbine engine as defined in any preceding claim, wherein the oil filler housing (40) comprises a peripheral flange (42) having a plurality of bores (41) through which fasteners can be inserted to threadedly fasten the oil filler housing (40) to correspondingly tapped bores in the oil tank housing (31).
An oil filler housing (40) for a gas turbine engine, the oil filler housing (40) comprising:
an oil filler port (43) for adding oil to an oil tank of the engine;

a shut-off valve (45) for preventing oil from escaping when a removable cap (44) is removed; and

an oil level indicator (50) for visually indicating an oil level in the oil tank.
The oil filler housing as defined in claim 5, wherein a top of the filler port (43) is higher than a maximum fill line of the oil level indicator (50) when the oil filler housing (40) is mounted to the oil tank housing (31).
The oil filler housing as defined in claim 5 or 6, wherein the oil filler housing (40) further comprises an anchor point (46) for receiving a flexible tether (48) for tethering a removable filler cap (44) to the oil filler housing (40) when the cap (44) has been removed from the filler port (43).
The oil filler housing as defined in claim 5, 6 or 7" wherein the oil filler housing (40) comprises a peripheral flange (42) having a plurality of bores (41) through which fasteners can be inserted to threadedly fasten the oil filler housing (40) to correspondingly tapped bores in the oil tank housing (31).
A filler housing for a gas turbine engine, the filler housing (40) comprising:
a single housing including a filler port (43) for adding a fluid to a fluid tank of the engine and at least one of a shut-off valve (45) for preventing fluid from escaping when a removable cap (44) is removed, a fluid level indicator (50), a filler cap (44), and an overfill valve, the filler housing (40) adapted for direct mounting in an opening (34) provided in a fluid reservoir of the gas turbine engine.
The filler housing as defined in claim 9, wherein the fluid is oil and the fluid reservoir is an oil tank.