US 4,525,995 AGranted

Oil scavening system for gas turbine engine

AssigneeWilliams International Corporation

InventorRalph J. Clark

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Abstract

A gas turbine engine intended for airborne applications in which several of the main bearings of the engine are contained in a bearing cavity and oil is scavenged from this cavity by allowing air from the high pressure region of the engine to leak into the cavity and then flow downwardly, together with entrained scavenge oil from the cavity, through an oversized cored passage housing a quill shaft driving the accessory gearbox for delivery to a crude separator at the bottom of the gearbox where the air is discharged to a low pressure region of the engine and the deaerated oil is delivered to the inlet of the scavenge pump. The leakage air flow effectively scavenges oil from the bearing cavity in all attitudes of the engine and also induces a flow of scavenge oil from the gearbox during upright operation. The gearbox also includes a cored passage which opens at its lower end in the separator and has its upper end arranged tangentially with respect to the topmost gear in the gearbox so that, during inverted operation of the engine, the topmost gear functions as a slinger to force scavenge oil from the gearbox to flow upwardly through the gearbox passage for delivery to the separator and thence to the scavenge pump.

Claims2

Dependent claims

A gas turbine engine comprising

A. a bearing cavity housing at least one bearing journaling a shaft of the engine;
B. means delivering lubricating oil to said cavity;
C. means allowing leakage airflow from a high pressure region of said engine into said cavity;
D. a scavenge oil pump arranged to deliver scavenge oil to an oil storage tank;
E. passage means interconnecting said cavity and the inlet of said scavenge oil pump;
F. vent means in said passage means adjacent the inlet of said pump venting said passage means to a low pressure region of the engine to induce a continuous flow of leakage air from said high pressure region into said cavity and induce a continuous flow of air and entrained scavenge oil through said passage means to the inlet of said pump;
and
G. separator means in said passage means adjacent the inlet of said pump arranged to receive the air and oil mixture flowing through said passage means and operative to separate the oil and air and deliver the oil to the pump inlet and the air to said vent means;
H. an accessory gearbox positioned at the bottom of the engine housing;
I. said scavenge pump being driven by said gearbox;
J. said separator means being located in the bottom of said gearbox;
K. the interior of said gearbox communicating with a nozzle which opens in said passage means adjacent the inlet of said separator;
L. the air and oil mixture flowing in said passage means from said cavity being arranged to induce a flow of scavenge oil from said gearbox through said nozzle and into said separator;
M. a plurality of gears journaled in said accessory gearbox;
and
N. gearbox passage means extending from a location adjacent the periphery of the topmost gear in said gearbox to said separator;
O. the inlet of the passage means in said gearbox being disposed tangentially with respect to the periphery of said topmost gear so that as said gear rotates during inverted operation of the engine the gear acts as a slinger to force scavenge oil from the gearbox to flow upwardly through said gearbox passage for delivery to said separator.

14 more elements

A gas turbine engine comprising

A. a bearing cavity housing at least one bearing journaling a shaft of the engine;
B. means delivering lubricating oil to said cavity;
C. means allowing leakage airflow from a high pressure region of said engine into said cavity;
D. a scavenge oil pump arranged to deliver scavenge oil to an oil storage tank;
E. passage means interconnecting said cavity and the inlet of said scavenge oil pump;
F. vent means in said passage means adjacent the inlet of said pump venting said passage means to a low pressure region of the engine to induce a continuous flow of leakage air from said high pressure region into said cavity and induce a continuous flow of air and entrained scavenge oil through said passage means to the inlet of said pump;
and
G. separator means in said passage means adjacent the inlet of said pump arranged to receive the air and oil mixture flowing through said passage means and operative to separate the oil and air and deliver the oil to the pump inlet and the air to said vent means;
H. an accessory gearbox positioned at the bottom of the engine housing;
I. said scavenge pump being driven by and adjacent said gearbox;
J. said separator means being located defined in the bottom of said gearbox;
K. the interior of said gearbox communicating with a nozzle which opens in said passage means adjacent the inlet of said separator;
L. the air and oil mixture flowing in said passage means from said cavity being arranged to induced a flow of scavenge oil from said gearbox through said nozzle and into said separator;
M. an accessory drive shaft extending downwardly from a location adjacent said engine shaft to a location adjacent said accessory gearbox, whereby to drive the gears within said gearbox, and
N. a scroll-shaped cavity at the interface of said gearbox and the engine housing adjacent and surrounding the lower end of said accessory drive shaft;
O. said passage means including an oversized passage extending downwardly from said bearing cavity to said scroll-shaped cavity and another passage extending downwardly from said scroll-shaped cavity to said separator means;
and
P. said accessory drive shaft running in said oversized passage but occupying only a portion of the passage cross section so as to permit the free flow of air and entrained oil downwardly through said passage to the scroll-shaped cavity and thence to the separator means.

15 more elements

Dependencies are inferred from the claim text.